Polyurea compositions and methods of use

ABSTRACT

Disclosed are polyurea compositions comprising the reaction products of a polyformal-isocyanate prepolymer and a curing agent comprising an amine. The compositions are useful as sealants in aerospace applications.

This application is a continuation-in-part of U.S. application Ser. No.14/184,772 filed on Feb. 20, 2014, now allowed, which is a continuationof U.S. application Ser. No. 13/934,286 filed on Jul. 3, 2013, issued asU.S. Pat. No. 8,729,193, which is a continuation of U.S. applicationSer. No. 13/051,002 filed on Mar. 18, 2011, issued as U.S. Pat. No.8,507,617, each of which is incorporated by reference in its entirety.

FIELD

The present disclosure relates to polyurea compositions and methods ofusing the polyurea compositions.

BACKGROUND

Thiol-terminated sulfur-containing polymers are known to be well-suitedfor use in various applications such as aerospace sealant compositions,due, in large part, to their fuel-resistance. Other desirable propertiesfor aerospace sealant compositions include low temperature flexibility,short curing time (the time required to reach a predetermined strength),and elevated-temperature resistance, among others. Sealant compositionsexhibiting at least some of these characteristics and containingthiol-terminated sulfur-containing polymers are described, for example,in U.S. Pat. Nos. 2,466,963; 4,366,307; 4,609,762; 5,225,472; 5,912,319;5,959,071; 6,172,179; 6,232,401; 6,372,849; and 6,509,418. Polysulfidesare also used in aerospace sealant applications where they provide hightensile strength, high shear strength, high-temperature thermalresistance, and fuel resistance, as disclosed, for example, in U.S. Pat.No. 7,638,162 and U.S. Publication No. 2005/0245695.

Polythioethers that are liquid at room temperature and pressure and thathave excellent low temperature flexibility and fuel resistance, such asare disclosed in U.S. Pat. No. 6,172,179, are also useful in aerospacesealant applications. Difunctional polythioethers having terminalhydroxyl groups prepared by reacting a hydroxyl compound with analdehyde are described, for example, in GB 850,178, U.S. Pat. No.3,959,227, and U.S. Pat. No. 3,997,614. Difunctional polythioethersterminated or capped with isocyanates are also known as disclosed, forexample, in GB 850,178, and in U.S. Pat. Nos. 3,290,382; 3,959,227; and3,997,614. Difunctional, linear polythioethers, however, often swellupon prolonged exposure to hydrocarbon fuel and other lubricants. On theother hand, sealants made using polyfunctional polythioethers, canexhibit good fuel resistance, hardness, and flexibility, but often withcompromised elongation.

It is desirable to provide compositions that are useful asfuel-resistant and water-resistant sealants with improved tensilestrength and elongation.

SUMMARY

Polyurea compositions for use as sealants having enhanced propertiesuseful for aerospace sealant applications are provided.

In a first aspect of the present disclosure, compositions are providedcomprising a polyformal-isocyanate prepolymer comprising the reactionproducts of reactants comprising a polyformal polyol and a firstdiisocyanate; and a curing agent comprising an amine.

In a second aspect of the present disclosure, compositions are providedcomprising the reaction products of reactants comprising apolyformal-isocyanate prepolymer comprising the reaction products of apolyformal polyol and a first aliphatic diisocyanate; apolythioether-isocyanate prepolymer comprising the reaction products ofa polythioether polyol and a second aliphatic diisocyanate; and anaromatic diamine.

In a third aspect of the present disclosure, apertures sealed with asealant comprising compositions provided by the present disclosure areprovided.

In a fourth aspect, compositions comprising an isocyanate-terminatedpolythioether prepolymer are disclosed, wherein theisocyanate-terminated polythioether comprises reaction products ofreactants comprising a polythioether polyol, wherein the polythioethercomprises reaction products of reactants comprising a thiol-terminatedpolythioether and a hydroxy-functional vinyl ether; and a diisocyanate.

In a fifth aspect, compositions comprising an isocyanate-terminatedpolythioether prepolymer are disclosed, wherein theisocyanate-terminated polythioether comprises reaction products ofreactants comprising a polythioether polyol, wherein the polythioetherpolyol comprises reaction products of reactants comprising athiol-terminated polythioether and a hydroxy-functional vinyl ether; anda diisocyanate; an curing agent comprising an aromatic amine; and apolyfunctional silane.

In a fifth aspect, methods of sealing a surface are disclosed,comprising mixing a an isocyanate-terminated polythioether prepolymerare disclosed, wherein the isocyanate-terminated polythioether comprisesreaction products of reactants comprising a polythioether polyol,wherein the polythioether comprises reaction products of reactantscomprising a thiol-terminated polythioether and a hydroxy-functionalvinyl ether; and a diisocyanate with a curing agent to provide anuncured sealant; applying the uncured sealant to a surface; and curingthe sealant to seal the surface.

The present invention is also directed to, inter alia, methods formaking such polyurea compositions, and sealants, including aerospacesealants, comprising such polyurea compositions.

BRIEF DESCRIPTION OF THE DRAWINGS

Those skilled in the art will understand that the drawings, describedherein, are for illustration purposes only. The drawings are notintended to limit the scope of the present disclosure.

FIG. 1 shows an example of a reaction for preparing a 4,4′-methylenedicyclohexyl diisocyanate (H₁₂MDI)-terminated thiodiglycolpolyformal-isocyanate prepolymer.

DETAILED DESCRIPTION Definitions

A dash (“-”) that is not between two letters or symbols is used toindicate a point of bonding for a substituent or between two atoms. Forexample, —CONH₂ is attached through the carbon atom.

“Aldehyde” refers to a compound of the formula CH(O)R where R ishydrogen or a hydrocarbon group such as an alkyl group, as definedherein. In certain embodiments, the aldehyde is C₁₋₁₀ aldehyde, C₁₋₆aldehyde, C₁₋₄ aldehyde, C₁₋₃ aldehyde, and in certain embodiments, C₁₋₂aldehyde. In certain embodiments, the aldehyde is formaldehyde. Incertain embodiments of the aldehyde, R is selected from hydrogen, C₁₋₆alkyl, C₇₋₁₂ phenylalkyl, substituted C₇₋₁₂ phenylalkyl, C₆₋₁₂cycloalkylalkyl, substituted C₆₋₁₂ cycloalkylalkyl, C₃₋₁₂ cycloalkyl,substituted C₃₋₁₂ cycloalkyl, C₆₋₁₂ aryl, and substituted C₆₋₁₂ aryl.

“Alkanediyl” refers to a diradical of a saturated, branched orstraight-chain, acyclic hydrocarbon group, having, for example, from 1to 18 carbon atoms (C₁₋₁₈), from 1-14 carbon atoms (C₁₋₁₄), from 1-6carbon atoms (C₁₋₆), from 1 to 4 carbon atoms (C₁₋₄), or from 1 to 3hydrocarbon atoms (C₁₋₃). In certain embodiments, the alkanediyl isC₂₋₁₄ alkanediyl, C₂₋₁₀ alkanediyl, C₂₋₈ alkanediyl, C₂₋₆ alkanediyl,C₂₋₄ alkanediyl, and in certain embodiments, C₂₋₃ alkanediyl. Examplesof alkanediyl groups include methane-diyl (—CH₂—), ethane-1,2-diyl(—CH₂CH₂—), propane-1,3-diyl and iso-propane-1,2-diyl (e.g., —CH₂CH₂CH₂—and —CH(CH₃)CH₂—), butane-1,4-diyl (—CH₂CH₂CH₂CH₂—), pentane-1,5-diyl(—CH₂CH₂CH₂CH₂CH₂—), hexane-1,6-diyl (—CH₂CH₂CH₂CH₂CH₂CH₂—),heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl, decane-1,10-diyl,dodecane-1,12-diyl, and the like.

“Alkoxy” refers to a —OR group where R is alkyl as defined herein.Examples of alkoxy groups include methoxy, ethoxy, n-propoxy,isopropoxy, and n-butoxy. In certain embodiments, the alkoxy group isC₁₋₈ alkoxy, C₁₋₆ alkoxy, C₁₋₄ alkoxy, and in certain embodiments, C₁₋₃alkoxy.

“Alkyl” refers to a monoradical of a saturated, branched orstraight-chain, acyclic hydrocarbon group having, for example, from 1 to20 carbon atoms, from 1 to 10 carbon atoms, from 1 to 6 carbon atoms,from 1 to 4 carbon atoms, or from 1 to 3 carbon atoms. Examples of alkylgroups include methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl,tert-butyl, n-hexyl, n-decyl, tetradecyl, and the like. In certainembodiments, the alkyl group is C₂₋₆ alkyl, C₂₋₄ alkyl, and in certainembodiments, C₂₋₃ alkyl.

“Aryl” refers to a monovalent aromatic hydrocarbon radical derived bythe removal of one hydrogen atom from a single carbon atom of a parentaromatic ring system. Aryl encompasses 5- and 6-membered carbocyclicaromatic rings, for example, benzene; bicyclic ring systems wherein atleast one ring is carbocyclic and aromatic, for example, naphthalene,indane, and tetralin; and tricyclic ring systems wherein at least onering is carbocyclic and aromatic, for example, fluorene. Arylencompasses multiple ring systems having at least one carbocyclicaromatic ring fused to at least one carbocyclic aromatic ring,cycloalkyl ring, or heterocycloalkyl ring. For example, aryl includes 5-and 6-membered carbocyclic aromatic rings fused to a 5- to 7-memberedheterocycloalkyl ring containing one or more heteroatoms selected fromN, O, and S. For such fused, bicyclic ring systems wherein only one ofthe rings is a carbocyclic aromatic ring, the point of attachment may beat the carbocyclic aromatic ring or the heterocycloalkyl ring. Examplesof aryl groups include derived from aceanthrylene, acenaphthylene,acephenanthrylene, anthracene, azulene, benzene, chrysene, coronene,fluoranthene, fluorene, hexacene, hexaphene, hexylene, as-indacene,s-indacene, indane, indene, naphthalene, octacene, octaphene, octalene,ovalene, penta-2,4-diene, pentacene, pentalene, pentaphene, perylene,phenalene, phenanthrene, picene, pleiadene, pyrene, pyranthrene,rubicene, triphenylene, trinaphthalene, and the like. In certainembodiments, the aryl group can have from 6 to 20 carbon atoms, and incertain embodiments, 6 to 12 carbon atoms, and in certain embodiments,from 6 to 10 carbon atoms. Aryl, however, does not encompass or overlapin any way with heteroaryl, separately defined herein. Hence, a multiplering system in which one or more carbocyclic aromatic rings is fused toa heterocycloalkyl aromatic ring, is heteroaryl, not aryl, as definedherein. In certain embodiments, an aryl group is phenyl.

“Arylalkyl” refers to an alkyl group in which one of the hydrogen atomsis replaced with an aryl group. In certain embodiments of an arylalkylgroup, a hydrogen atom on the terminal carbon atom of an alkyl group isreplaced with an aryl group. In certain embodiments of arylalkyl, thearyl group is a C₆₋₁₂ aryl group, in certain embodiments a C₆₋₁₀ arylgroup, and in certain embodiments, a phenyl or naphthyl group. Incertain embodiments, the alkanediyl portion of an arylalkyl group maybe, for example, C₁₋₁₀ alkanediyl, C₁₋₆ alkanediyl, C₁₋₄ alkanediyl,C₁₋₃ alkanediyl, propane-1,3-diyl, ethane-1,2-diyl, or methane-diyl. Incertain embodiments, the arylalkyl group is C₇₋₁₈ arylalkyl, C₇₋₁₆arylalkyl, C₇₋₁₂ arylalkyl, C₇₋₁₀ arylalkyl, or C₇₋₉ arylalkyl. Forexample, C₇₋₉ arylalkyl can include a C₁₋₃ alkanediyl group bonded to aphenyl group.

“Cycloalkylalkyl” refers to an alkyl group in which one of the hydrogenatoms is replaced with a cycloalkyl group. In certain embodiments of thecycloalkylalkyl group, a hydrogen atom on the terminal carbon atom of analkyl group is replaced with a cycloalkyl group. In certain embodimentsof cycloalkylalkyl, the cycloalkyl group is a C₃₋₆ cycloalkyl group, incertain embodiments a C₅₋₆ cycloalkyl group, and in certain embodiments,a cyclopropyl, a cyclobutyl, a cyclopentyl, or a cyclohexyl group. Incertain embodiments, the alkanediyl portion of a cycloalkylalkyl groupmay be, for example, C₁₋₁₀ alkanediyl, C₁₋₆ alkanediyl, C₁₋₄ alkanediyl,C₁₋₃ alkanediyl, propane-1,3-diyl, ethane-1,2-diyl, or methane-diyl. Incertain embodiments, the cycloalkylalkyl group is C₄₋₁₆ cycloalkylalkyl,C₄₋₁₂ cycloalkylalkyl, C₄₋₁₀ cycloalkylalkyl, C₆₋₁₂ cycloalkylalkyl, orC₆₋₉ cycloalkylalkyl. For example, C₆₋₉ cycloalkylalkyl includes a C₁₋₃alkanediyll group bonded to a cyclopentyl or to a cyclohexyl group.

“Alkanecycloalkane” refers to a saturated hydrocarbon group having oneor more cycloalkyl and/or cycloalkanediyl groups and one or more alkyland/or alkanediyl groups, where cycloalkyl, cycloalkanediyl, alkyl, andalkanediyl are defined herein. In certain embodiments, each cycloalkyland/or cycloalkanediyl group(s) is C₃₋₆, C₅₋₆, and in certainembodiments, cyclohexyl or cyclohexanediyl. In certain embodiments, eachalkyl and/or alkanediyl group(s) is C₁₋₆, C₁₋₄, C₁₋₃, and in certainembodiments, methyl, methanediyl, ethyl, or ethane-1,2-diyl. In certainembodiments, an alkanecycloalkane group is C₄₋₁₈ alkanecycloalkane,C₄₋₁₆ alkanecycloalkane, C₄₋₁₂ alkanecycloalkane, C₄₋₈alkanecycloalkane, C₆₋₁₂ alkanecycloalkane, C₆₋₁₀ alkanecycloalkane, andin certain embodiments, C₆₋₉ alkanecycloalkane. Examples ofalkanecycloalkane groups include 1,1,3,3-tetramethylcyclohexane andcyclohexylmethane.

“Alkanecycloalkanediyl” refers to a diradical of an alkanecycloalkanegroup. In certain embodiments, an alkanecycloalkanediyl group is C₄₋₁₈alkanecycloalkanediyl, C₄₋₁₆ alkanecycloalkanediyl, C₄₋₁₂alkanecycloalkanediyl, C₄₋₈ alkanecycloalkanediyl, C₆₋₁₂alkanecycloalkanediyl, C₆₋₁₀ alkanecycloalkanediyl, and in certainembodiments, C₆₋₉ alkanecycloalkanediyl. Examples ofalkanecycloalkanediyl groups include1,1,3,3-tetramethylcyclohexane-1,5-diyl and cyclohexylmethane-4,4′-diyl.

“Cycloalkanediyl” refers to a diradical saturated monocyclic orpolycyclic hydrocarbon group. In certain embodiments, thecycloalkanediyl group is C₃₋₁₂ cycloalkanediyl, C₃₋₈ cycloalkanediyl,C₃₋₆ cycloalkanediyl, and in certain embodiments, C₅₋₆ cycloalkanediyl.Examples of cycloalkanediyl groups include cyclohexane-1,4-diyl,cyclohexane-1,3-diyl, and cyclohexane-1,2-diyl.

“Cycloalkyl” refers to a saturated monocyclic or polycyclic hydrocarbonmonoradical group. In certain embodiments, the cycloalkyl group is C₃₋₁₂cycloalkyl, C₃₋₈ cycloalkyl, C₃₋₆ cycloalkyl, and in certainembodiments, C₅₋₆ cycloalkyl.

“Heteroalkyl” refers to an alkyl group in which one or more of thecarbon atoms are replaced with a heteroatom, such as N, O, S, or P. Incertain embodiments of heteroalkyl, the heteroatom is selected from Nand O.

“Heteroaryl” refers to a monovalent heteroaromatic radical derived bythe removal of one hydrogen atom from a single atom of a parentheteroaromatic ring system. Heteroaryl encompasses multiple ring systemshaving at least one heteroaromatic ring fused to at least one otherring, which can be aromatic or non-aromatic. Heteroaryl encompasses 5-to 7-membered aromatic, monocyclic rings containing one or more, forexample, from 1 to 4, or in certain embodiments, from 1 to 3,heteroatoms selected from N, O, S, and P with the remaining ring atomsbeing carbon; and bicyclic heterocycloalkyl rings containing one ormore, for example, from 1 to 4, or in certain embodiments, from 1 to 3,heteroatoms selected from N, O, S, and P, with the remaining ring atomsbeing carbon and wherein at least one heteroatom is present in anaromatic ring. For example, heteroaryl includes a 5- to 7-memberedheteroaromatic ring fused to a 5- to 7-membered cycloalkyl ring. Forsuch fused, bicyclic heteroaryl ring systems wherein only one of therings contains one or more heteroatoms, the point of attachment may beat the heteroaromatic ring or the cycloalkyl ring. In certainembodiments, where the total number of N, O, S, and P atoms in theheteroaryl group exceeds one, the heteroatoms are not adjacent to oneanother. In certain embodiments, the total number of N, O, S, and Patoms in the heteroaryl group is not more than two. In certainembodiments, the total number of N, O, S, and P atoms in the aromaticheterocycle is not more than one. Heteroaryl does not encompass oroverlap with aryl as defined herein. Examples of heteroaryl groupsinclude groups derived from acridine, arsindole, carbazole, α-carboline,chromane, chromene, cinnoline, furan, imidazole, indazole, indole,indoline, indolizine, isobenzofuran, isochromene, isoindole,isoindoline, isoquinoline, isothiazole, isoxazole, naphthyridine,oxadiazole, oxazole, perimidine, phenanthridine, phenanthroline,phenazine, phthalazine, pteridine, purine, pyran, pyrazine, pyrazole,pyridazine, pyridine, pyrimidine, pyrrole, pyrrolizine, quinazoline,quinoline, quinolizine, quinoxaline, tetrazole, thiadiazole, thiazole,thiophene, triazole, xanthene, and the like. In certain embodiments, theheteroaryl group is C₅₋₂₀ heteroaryl, C₅₋₁₂ heteroaryl, C₅₋₁₀heteroaryl, and in certain embodiments, C₅₋₆ heteroaryl. In certainembodiments, heteroaryl groups are those derived from thiophene,pyrrole, benzothiophene, benzofuran, indole, pyridine, quinoline,imidazole, oxazole, or pyrazine.

“Ketone” refers to a compound of the formula CO(R)₂ where each R is ahydrocarbon group. In certain embodiments of a ketone, each R isindependently selected from C₁₋₆ alkyl, C₇₋₁₂ phenylalkyl, substitutedC₇₋₁₂ phenylalkyl, C₆₋₁₂ cycloalkylalkyl, and substituted C₆₋₁₂cycloalkylalkyl. In certain embodiments of the ketone, each R isindependently selected from methyl, ethyl, and propyl. In certainembodiments, the ketone is selected from propan-2-one, butan-2-one,pentan-2-one, and pentan-3-one. In certain embodiments of the ketone,each R is independently selected from C₁₋₆ alkyl, C₇₋₁₂ phenylalkyl,substituted C₇₋₁₂ phenylalkyl, C₆₋₁₂ cycloalkylalkyl, substituted C₆₋₁₂cycloalkylalkyl, C₃₋₁₂ cycloalkyl, substituted C₃₋₁₂ cycloalkyl, C₆₋₁₂aryl, and substituted C₆₋₁₂ aryl.

“Phenylalkyl” refers to an alkyl group in which one of the hydrogenatoms are replaced with a phenyl group. In certain embodiments of thephenylalkyl group, one of the hydrogen atoms of the terminal carbon atomof an alkyl group is replaced with a phenyl group. In certainembodiments, the phenylalkyl group is C₇₋₁₂ phenylalkyl, C₇₋₁₀phenylalkyl, C₇₋₉ phenylalkyl, and in certain embodiments, benzyl.

“Substituted” refers to a group in which one or more hydrogen atoms areeach independently replaced with the same or different substituent(s).In certain embodiments, the substituent is selected from halogen,—S(O)₂OH, —S(O)₂, —SH, —SR where R is C₁₋₆ alkyl, —COOH, —NO₂, —NR₂where each R is independently selected from hydrogen and C₁₋₃ alkyl,—CN, ═O, C₁₋₆ alkyl, C₁₋₃ alkyl, —CF₃, —OH, phenyl, C₂₋₆ heteroalkyl,C₅₋₆ heteroaryl, C₁₋₆ alkoxy, and —COR where R is C₁₋₆ alkyl. In certainembodiments, the substituent is selected from —OH, —NH₂, and C₁₋₃ alkyl.

Unless otherwise made explicit, a polymer encompasses one or more typesof polymers. For example, reference to a polyformal polyol includes asingle type of polyformal polyol such as a thiodiglycol polyformalpolyol, and a mixture of different types of polyformal polyols.Similarly, unless otherwise made explicit, reference to a compound suchas, for example, a compound of a specific formula or a diisocyanate,refers to a single type of compound or diisocyanate and more than onetype of compound or diisocyanate.

For purposes of the following detailed description, it is to beunderstood that embodiments provided by the present disclosure mayassume various alternative variations and step sequences, except whereexpressly specified to the contrary. Moreover, other than in anyoperating examples, or where otherwise indicated, all numbersexpressing, for example, quantities of ingredients used in thespecification and claims are to be understood as being modified in allinstances by the term “about.” Accordingly, unless indicated to thecontrary, the numerical parameters set forth in the followingspecification and attached claims are approximations that may varydepending upon the desired properties to be obtained by the presentinvention. At the very least, and not as an attempt to limit theapplication of the doctrine of equivalents to the scope of the claims,each numerical parameter should at least be construed in light of thenumber of reported significant digits and by applying ordinary roundingtechniques.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the invention are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. Any numerical value, however, inherently contains certainerrors necessarily resulting from the standard variation found in theirrespective testing measurements.

Also, it should be understood that any numerical range recited herein isintended to include all sub-ranges subsumed therein. For example, arange of “1 to 10” is intended to include all sub-ranges between (andincluding) the recited minimum value of 1 and the recited maximum valueof 10, that is, having a minimum value equal to or greater than 1 and amaximum value of equal to or less than 10.

Reference is now made in detail to certain embodiments of compounds,compositions, and methods. The disclosed embodiments are not intended tobe limiting of the claims. To the contrary, the claims are intended tocover all alternatives, modifications, and equivalents.

Polyurea Compositions

In certain embodiments, compositions provided by the present disclosurecomprise a polyformal-isocyanate prepolymer and a curing agentcomprising an amine, wherein the polyformal-isocyanate prepolymercomprises the reaction products of reactants comprising a polyformalpolyol and a first diisocyanate.

In certain embodiments, the polyformal polyol comprises a polyformalpolyol selected from a polyformal diol, a polyformal polyol having atleast three hydroxyl groups per polyformal molecule, and a combinationthereof. In certain embodiments, the polyformal polyol comprises apolyformal polyol selected from a polyformal diol, a polyformal triol,and a combination thereof. In certain embodiments, the polyformal polyolcomprises a combination of a polyformal diol and a polyformal triol.

In certain embodiments, a polyformal polyol comprises: (i) the reactionproducts of reactants comprising a sulfur-containing diol; and areactant selected from an aldehyde, a ketone, and a combination thereof;(ii) the reaction products of reactants comprising a sulfur-containingdiol; a polyol containing at least three hydroxyl groups per polyolmolecule; and a reactant selected from an aldehyde, a ketone, and acombination thereof; and (iii) a combination of (i) and (ii).

In certain embodiments of reaction (i), the sulfur-containing diolcomprises a single type of sulfur-containing diol, and in certainembodiments, comprises a combination of sulfur-containing diols.

In certain embodiments, the polyformal polyol comprises the reactionproducts of a sulfur-containing diol; and a reactant selected from analdehyde, a ketone, and a combination thereof. In certain embodiments ofthe reaction, the sulfur-containing diol comprises a diol of Formula(1):

where each R³ is independently selected from C₂₋₆ alkanediyl. In certainembodiments of a sulfur-containing diol of Formula (1), each R³ is thesame and in certain embodiments, each R³ is different. In certainembodiments, each R³ is selected from C₂₋₅ alkanediyl, C₂₋₄ alkanediyl,C₂₋₃ alkanediyl, and in certain embodiments, each R³ is ethane-1,2-diyl.In certain embodiments of the reaction, the sulfur-containing diolcomprises a sulfur-containing diol selected from 2,2′-thiodiethanol,3,3′-thiobis(propan-1-ol), 4,4′-thiobis(butan-1-ol), and a combinationof any of the foregoing. In certain embodiments of the reaction, thesulfur-containing diol comprises 2,2′-thiodiethanol.

In certain embodiments of reaction (i), the reactant is an aldehyde. Incertain embodiments in which the reactant is an aldehyde, the aldehydecomprises a C₁₋₆ aldehyde, a C₁₋₄ aldehyde, a C₁₋₃ aldehyde, and incertain embodiments, a C₁₋₂ aldehyde. In certain embodiments, thealdehyde is formaldehyde. In certain embodiments in which the reactantis formaldehyde, the formaldehyde is provided as paraformaldehyde.

In certain embodiments of reaction (i), the reactant is a ketone. Incertain embodiments in which the reactant is a ketone, the ketone hasthe formula COR₂ where each R is independently selected from C₁₋₆ alkyl,C₇₋₁₂ phenylalkyl, substituted C₇₋₁₂ phenylalkyl, C₆₋₁₂ cycloalkylalkyl,substituted C₆₋₁₂ cycloalkylalkyl, C₃₋₁₂ cycloalkyl, substituted C₃₋₁₂cycloalkyl, C₆₋₁₂ aryl, and substituted C₆₋₁₂ aryl. In certainembodiments of a ketone, each R is independently selected from methyl,ethyl, and propyl. In certain embodiments, a ketone is selected frompropan-2-one, butan-2-one, pentan-2-one, and pentan-3-one.

In certain embodiments of reaction (i), the polyformal polyol comprisesthe reaction product of reactants comprising 2,2′-thiodiethanol andformaldehyde, and is referred to herein as thiodiglycol polyformal.

In certain embodiments, a polyformal polyol has a number averagemolecular weight from 200 to 6,000 Daltons, from 500 to 5,000 Daltons,from 1,000 to 5,000 Daltons, from 1,500 to 4,000 Daltons, and in certainembodiments, from 2,000 to 3,600 Daltons.

In certain embodiments, polyformal polyols provided by the presentdisclosure comprise: (ii) the reaction products of reactants comprisinga sulfur-containing diol; a polyol containing at least three (3)hydroxyl groups per polyol molecule; and a reactant selected from analdehyde, a ketone, and a combination thereof. The reactants maycomprise one or more types of sulfur-containing diol, one or more typesof polyol, and/or one or more types of aldehyde and/or ketone.

In certain embodiments of reaction (ii), the sulfur-containing diolcomprises a diol of Formula (1) where each R³ is independently selectedfrom C₂₋₆ alkanediyl. In certain embodiments of reaction (ii), thesulfur-containing diol comprises a sulfur-containing diol selected from2,2′-thiodiethanol, 3,3′-thiobis(propan-1-ol), 4,4′-thiobis(butan-1-ol),and a combination of any of the foregoing. In certain embodiments of thereaction, the sulfur-containing diol comprises 2,2′-thiodiethanol.

In certain embodiments of reaction (ii), the sulfur-containing diolcomprises a single type of sulfur-containing diol, and in certainembodiments, comprises a combination of sulfur-containing diols.

In certain embodiments of reaction (ii), a polyol contains at leastthree hydroxyl groups per polyol molecule. For example, a polyol maycontain from three to ten hydroxyl groups per polyol molecule, fromthree to eight hydroxyl groups per polyol molecule, from three to sixhydroxyl groups per polyol molecule, and in certain embodiments, fromthree to four hydroxyl groups per polyol molecule. In certainembodiments, a polyol contains four hydroxyl groups per polyol molecule,and in certain embodiments, a polyol contains three hydroxyl groups perpolyol molecule. The polyol may be a single type of polyol or may be acombination of different polyols having the same or different number ofhydroxyl groups per molecule.

In certain embodiments, a polyol has the formula E(OH)_(z), where z isan integer from 3 to 6, and E represents the core of the z-valentpolyol. In certain embodiments, a polyol comprises a triol (z is 3) ofFormula (2):

where each R¹¹ is independently C₁₋₆ alkanediyl; and in certainembodiments, a polyol comprises a triol of Formula (3):

where each R¹¹ is independently C₁₋₆ alkanediyl. In certain embodimentsof a polyol of Formula (2) and Formula (3), each R¹¹ may beindependently selected from C₁₋₄ alkanediyl, and in certain embodiments,from C₁₋₃ alkanediyl. In certain embodiments of a polylol of Formula (2)and Formula (3), each R¹¹ may be the same, and in certain embodiments,each R¹¹ may be different. In certain embodiments of a polyol of Formula(2) and Formula (3), each R¹¹ is selected from methanediyl,ethane-1,2-diyl, propane-1,3-diyl, and in certain embodiments,butane-1,4-diyl.

In certain embodiments of reaction (ii), the reactant is an aldehyde. Incertain embodiments in which the reactant is an aldehyde, the aldehydecomprises a C₁₋₆ aldehyde, a C₁₋₄ aldehyde, a C₁₋₃ aldehyde, and incertain embodiments, a C₁₋₂ aldehyde. In certain embodiments, thealdehyde comprises an alkyl and is selected from acetaldehyde,propionaldehyde, isobutyraldehyde, and butyraldehyde. In certainembodiments, the aldehyde is formaldehyde. In certain embodiments inwhich the reactant is formaldehyde, the formaldehyde is provided asparaformaldehyde.

In certain embodiments of reaction (ii), the reactant is a ketone. Incertain embodiments in which the reactant is a ketone, the ketone hasthe formula C(O)R₂ where each R is independently selected from C₁₋₆alkyl, C₇₋₁₂ phenylalkyl, substituted C₇₋₁₂ phenylalkyl, C₆₋₁₂cycloalkylalkyl, substituted C₆₋₁₂ cycloalkylalkyl, C₃₋₁₂ cycloalkyl,substituted C₃₋₁₂ cycloalkyl, C₆₋₁₂ aryl, and substituted C₆₋₁₂ aryl. Incertain embodiments of a ketone, each R is independently selected frommethyl, ethyl, and propyl. In certain embodiments, a ketone is selectedfrom propan-2-one, butan-2-one, pentan-2-one, pentan-3-one, and3-methylbutan-2-one.

In certain embodiments of reaction (ii), a polyformal polyol comprisesthe reaction product of reactants comprising 2,2′-thiodiethanol, apolyol, and formaldehyde. In certain embodiments of reaction (ii), apolyformal polyol comprises the reaction product of reactants comprising2,2′-thiodiethanol, a triol, and formaldehyde. In certain embodiments, apolyformal polyol provided by the present disclosure comprises thereaction product of reactants comprising 2,2′-thiodiethanol,formaldehyde, and a triol of Formula (2). In certain embodiments, apolyformal polyol provided by the present disclosure comprises thereaction product of reactants comprising 2,2′-thiodiethanol,formaldehyde, and a triol of Formula (3).

In embodiments in which the one or more polyols used to form polyformalpolyols provided by the present disclosure have the same number ofhydroxyl groups, the polyformal polyol will have a hydroxylfunctionality approximately equivalent to that of the one or morepolyols. For example, when a polyol having a hydroxyl functionality ofthree or a combination of polyols in which each of the polyols in thecombination has a hydroxyl functionality of three is used to prepare apolyformal polyol, the polyformal polyol will have a hydroxylfunctionality of three. In certain embodiments, a polyformal polyol mayhave an average hydroxyl functionality of three, four, five, and incertain embodiments, six.

When polyols having different hydroxyl functionalities are used toprepare polyformal polyols, the polyformal polyols can exhibit a rangeof functionalities. For example, polyformal polyols provided by thepresent disclosure may have an average hydroxyl functionality from 3 to12, from 3 to 9, from 3 to 6, from 3 to 4, and in certain embodiments,from 3.1 to 3.5. In certain embodiments, a polyformal polyol having anaverage hydroxyl functionality from three to four may be prepared byreacting a combination of one or more polyols having a hydroxylfunctionality of three and one or more polyols having a hydroxylfunctionality of four.

In certain embodiments, polyformal polyols provided by the presentdisclosure have a hydroxyl number from 10 to 100, from 20 to 80, from 20to 60, from 20 to 50, and in certain embodiments, from 20 to 40. Thehydroxyl number is the hydroxyl content of the polyformal polyol, andmay be determined, for example, by acetylating the hydroxyl groups andtitrating the resultant acid against potassium hydroxide. The hydroxylnumber is the weight of potassium hydroxide in milligrams that willneutralize the acid from one gram of the polyformal polyol.

In certain embodiments, a polyformal polyol provided by the presentdisclosure has a number average molecular weight from 200 to 6,000Daltons, from 500 to 5,000 Daltons, from 1,000 to 4,000 Daltons, from1,500 to 3,500 Daltons, and in certain embodiments, from 2,000 Daltonsto 3,000 Daltons.

In certain embodiments, a polyformal polyol comprises a polyformalpolyol selected from a polyformal polyol of Formula (4), a polyformalpolyol of Formula (5), and a combination thereof:

where w is selected from an integer from 1 to 50; z is selected from aninteger from 3 to 6; each R³ is independently selected from C₂₋₆alkanediyl; each R⁴ is independently selected from hydrogen, C₁₋₆ alkyl,C₇₋₁₂ phenylalkyl, substituted C₇₋₁₂ phenylalkyl, C₆₋₁₂ cycloalkylalkyl,substituted C₆₋₁₂ cycloalkylalkyl, C₃₋₁₂ cycloalkyl, substituted C₃₋₁₂cycloalkyl, C₆₋₁₂ aryl, and substituted C₆₋₁₂ aryl; and E represents thecore of an z-valent parent polyol E(OH)_(z).

In certain embodiments of a polyformal polyol of Formula (4) and/orFormula (5), each R³ is ethane-1,2-diyl and each R⁴ is hydrogen.

In certain embodiments, a polyformal polyol has the structure of Formula(4) and/or Formula (5), where w is selected from an integer from 1 to50; each R³ is independently C₂₋₆ alkanediyl; and each R⁴ isindependently selected from hydrogen, C₁₋₆ alkyl, C₇₋₁₂ phenylalkyl,substituted C₇₋₁₂ phenylalkyl, C₆₋₁₂ cycloalkylalkyl, substituted C₆₋₁₂cycloalkylalkyl, C₃₋₁₂ cycloalkyl, substituted C₃₋₁₂ cycloalkyl, C₆₋₁₂aryl, and substituted C₆₋₁₂ aryl.

In certain embodiments of a polyformal polyol of Formula (4) and/orFormula (5), each R³ is independently selected from C₂₋₆ alkanediyl,C₂₋₄ alkanediyl, C₂₋₃ alkanediyl, and in certain embodiments,ethane-1,2-diyl. In certain embodiments of a polyformal polyol ofFormula (4) and/or Formula (5), each R³ is ethane-1,2-diyl.

In certain embodiments of a polyformal polyol of Formula (4) and/orFormula (5), each R⁴ is independently selected from hydrogen, C₁₋₆alkyl, C₁₋₄ alkyl, C₁₋₃ alkyl, and in certain embodiments, C₁₋₂ alkyl.In certain embodiments of a polyformal polyol of Formula (4) and/orFormula (5), each R⁴ is hydrogen, in certain embodiments, methyl, and incertain embodiments, ethyl.

In certain embodiments of a polyformal polyol of Formula (4) and/orFormula (5), each R³ is the same and is selected from a C₂₋₃ alkanediylsuch as ethane-1,2-diyl and propane-1,3-diyl; and each R⁴ is the sameand is selected from hydrogen and C₁₋₃ alkyl such as methyl, ethyl, andpropyl. In certain embodiments of a polyformal polyol of Formula (4)and/or Formula (5), each R³ is ethane-1,2-diyl. In certain embodimentsof a polyformal polyol of Formula (4) and/or Formula (5), each R⁴ ishydrogen. In certain embodiments of a polyformal polyol of Formula (4)and/or Formula (5), each R³ is ethane-1,2-diyl, and each R⁴ is hydrogen.

In certain embodiments of a polyformal polyol of Formula (4) and/orFormula (5), w is an integer from 1 to 50, an integer from 2 to 40, aninteger from 4 to 30, and in certain embodiments, w is an integer from 7to 30.

In certain embodiments, a polyformal polyol of Formula (4) and/orFormula (5) has a number average molecular weight from 200 to 6,000Daltons, from 500 to 5,000 Daltons, from 1,000 to 5,000 Daltons, from1,500 to 4000 Daltons, and in certain embodiments, from 2,000 to 3,600Daltons.

In certain embodiments of a polyformal polyol of Formula (5), z is 3, zis 4, z is 5, and in certain embodiments, z is 6.

In certain embodiments of a polyformal polyol of Formula (5) where z is3, the parent polyol E(OH)_(z) is a triol of Formula (2):

where each R¹¹ is independently C₁₋₆ alkanediyl, and in certainembodiments, a triol of Formula (3):

where each R¹¹ is independently C₁₋₆ alkanediyl. Accordingly, in theseembodiments E has the structure:

respectively, where each R¹¹ is independently C₁₋₆ alkanediyl.

A polyformal-isocyanate prepolymer may be formed by reacting adiisocyanate with a polyformal polyol. In certain embodiments, the molarratio of the diisocyanate to the polyformal polyol is greater than 2 to1, greater than 2.3 to 1, greater than 2.6 to 1, and in certainembodiments, greater than 3 to 1.

Polyformal-isocyanate prepolymers may be formed by first reacting apolyformal polyol with a diisocyanate to form a diisocyanate-polyformalpolyol adduct. The adduct may then be oligomerized by reacting withadditional polyformal polyol and diisocyanate to provide adiisocyanate-terminated polyformal oligomer. In certain embodiments, thepolyformal-isocyanate prepolymer comprises a combination of unreacteddiisocyanate, the 2:1 diisocyanate-polyformal polyol adduct, and thediisocyanate-terminated polyformal oligomer. An example of a reactionsequence using thiodiglycol polyformal and H₁₂MDI to form aH₁₂MDI-terminated thiodiglycol polyformal-isocyanate prepolymer is shownin FIG. 1, where w is an integer from 1 to 50, and y is an integer from2 to 15.

The reaction used to prepare a polyformal polyol may take place in thepresence of an acidic catalyst, such as sulfuric acid, sulfonic acid, ora combination thereof. In certain embodiments, a sulfonic acid may beused. Examples of sulfonic acids include alkyl sulfonic acids such asmethane sulfonic acid, ethane sulfonic acid tert-butane sulfonic acid,2-propane sulfonic acid, and cyclohexyl sulfonic acid; alkene sulfonicacids such as α-olefin sulfonic acid, dimerized α-olefin sulfonic acid,and 2-hexene sulfonic acid; aromatic sulfonic acids such as para-toluenesulfonic acids, benzene sulfonic acid, and naphthalene sulfonic acid;and polymer-supported sulfonic acids such as AMBERLYST™ sulfonic acidcatalysts available from Dow Chemical.

In certain embodiments, a polyformal-isocyanate prepolymer comprises thereaction products of a polyformal polyol and an aliphatic diisocyanate.

Examples of suitable aliphatic diisocyanates for reacting with apolyformal polyol include, 1,6-hexamethylene diisocyanate,1,5-diisocyanato-2-methylpentane, methyl-2,6-diisocyanatohexanoate,bis(isocyanatomethyl)cyclohexane, 1,3-bis(isocyanatomethyl)cyclohexane,2,2,4-trimethylhexane 1,6-diisocyanate, 2,4,4-trimethylhexane1,6-diisocyanate, 2,5(6)-bis(isocyanatomethyl)cyclo[2.2.1.]heptane,1,3,3-trimethyl-1-(isocyanatomethyl)-5-isocyanatocyclohexane,1,8-diisocyanato-2,4-dimethyloctane,octahydro-4,7-methano-1H-indenedimethyl diisocyanate, and1,1′-methylenebis(4-isocyanatocyclohexane), and 4,4′-methylenedicyclohexyl diisocyanate (H₁₂MDI).

Examples of suitable alicyclic aliphatic diisocyanates for reacting witha polyformal polyol include isophorone diisocyanate (IPDI), cyclohexanediisocyanate, methylcyclohexane diisocyanate,bis(isocyanatomethyl)cyclohexane, bis(isocyanatocyclohexyl)methane,bis(isocyanatocyclohexyl)-2,2-propane,bis(isocyanatocyclohexyl)-1,2-ethane,2-isocyanatomethyl-3-(3-isocyanatopropyl)-5-isocyanatomethyl-bicyclo[2.2.1]-heptane,2-isocyanatomethyl-3-(3-isocyanatopropyl)-6-isocyanatomethyl-bicyclo[2.2.1]-heptane,2-isocyanatomethyl-2-(3-isocyanatopropyl)-5-isocyanatomethyl-bicyclo[2.2.1]-heptane,2-isocyanatomethyl-2-(3-isocyanatopropyl)-6-isocyanatomethyl-bicyclo[2.2.1]-heptane,2-isocyanatomethyl-3-(3-isocyanatopropyl)-6-(2-isocyanatoethyl)-bicyclo[2.2.1]-heptane,2-isocyanatomethyl-2-(3-isocyanatopropyl)-5-(2-isocyanatoethyl)-bicyclo[2.2.1]-heptane,and2-isocyanatomethyl-2-(3-isocyanatopropyl)-6-(2-isocyanatoethyl)-bicyclo[2.2.1]-heptane.

In certain embodiments, a polyformal-isocyanate prepolymer comprises thereaction products of a polyformal polyol and an aliphatic diisocyanateselected from IPDI, an HDI trimer, H₁₂MDI, and a combination of any ofthe foregoing. Examples of HDI trimers include, for example,1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(6-isocyanatohexyl),DESMODUR® N3300, DESMODUR® N3368, DESMODUR® N3386, DESMODUR® N3390,DESMODUR® N3600, DESMODUR® N3800, DESMODUR® XP2731, DESMODUR® XP2742,DESMODUR® XP2675, and DESMODUR® N2714.

In certain embodiments, a polyformal-isocyanate prepolymer comprises thereaction products of a polyformal polyol and 4,4′-methylene dicyclohexyldiisocyanate (H₁₂MDI).

In certain embodiments, an amine comprises a polyamine, such as adiamine. In certain embodiments, an amine curing agent comprises anaromatic diamine such as, for example, dimethylthiotoluenediamine,diethyltoluenediamine, or a combination thereof. In certain embodiments,an aromatic diamine comprises dimethylthiotoluenediamine such asETHACURE® 300, which comprises 95%-97% dimethylthiotoluene diamine,2%-3% monomethylthiotoluene diamine, where the dimethylthiotoluenediamine comprises a combination of the 3,5-dimethylthio-2,6-toluenediamine, and 3,5-dimethylthio-2,4-toluene diamine as the major isomer.In certain embodiments, an aromatic diamine comprisesdiethylthiotoluenediamine such as ETHACURE® 100, which comprises 75%-81%diethyltoluene-2,4-diamine and 18%-20% 3,5-diethyltoluene-2,6-diamine.In certain embodiments, the composition comprises a molar equivalentexcess of isocyanate to amine, such as, for example, a molar equivalentexcess from 1.01 to 1.2, from 1.02 to 1.1, from 1.02 to 1.08, from 1.03to 1.07, and in certain embodiments, 1.05.

In certain embodiments, a composition provided by the present disclosurecomprises a polyformal-isocyanate prepolymer comprising the reactionproducts of reactants comprising a polyformal polyol and a firstdiisocyanate, a polythioether-isocyanate prepolymer comprising thereaction products of reactants comprising a polythioether polyol and asecond diisocyanate, and a curing agent comprising an amine.

In certain embodiments, a polythioether polyol comprises a polythioetherpolyol selected from a polythioether diol, a polythioether triol, and acombination thereof. In certain embodiments, a polythioether polyolcomprises a combination of a polythioether diol and a polythioethertriol.

A polythioether polyol refers to a polythioether having terminalhydroxyl groups. As used herein, the term “polythioether” refers to acompound containing at least two thioether linkages, that is“—CR₂—S—CR₂—” groups. In certain embodiments, such compounds arepolymers. As used herein, “polymer” refers to oligomers and bothhomopolymers and copolymers. Unless stated otherwise, molecular weightsare number average molecular weights for polymeric materials indicatedas “Mn” as may be determined, for example, by gel permeationchromatography using a polystyrene standard in an art-recognized manner.

In certain embodiments, the polythioether polyol comprises a polyolselected from a polythioether polyol of Formula (6); a polythioetherpolyol of Formula (7), and a combination thereof:

HO—R¹—[—S—(CH₂)₂—O—[—R²—O-]_(m)—(CH₂)₂—S—R¹—]_(n)—OH  (6)

{HO—R¹—[—S—(CH₂)₂—O—[—R²—O-]_(m)—(CH₂)₂—S—R¹—]_(n)—O-}_(z)—B  (7)

where each R¹ is independently selected from C₂₋₆ alkanediyl, C₆₋₈cycloalkanediyl, C₆₋₁₀ alkanecycloalkanediyl,—[(—CH₂—)_(p)—X—]_(q)—(—CH₂—)_(r), and—[(—CH₂—)_(p)—X-]_(q)—(—CH₂—)_(r)—, wherein at least one —CH₂— group issubstituted with a methyl group; each R² is independently selected fromC₂₋₆ alkanediyl, C₆₋₈ cycloalkanediyl, C₆₋₁₀ alkanecycloalkanediyl, and—[(—CH₂—)_(p)—X-]_(q)—(—CH₂—)_(r)—; X is selected from —O—, —S— and—NR¹⁰—, where R¹⁰ is selected from hydrogen and methyl; Z represents thecore of an z-valent polyfunctionalizing agent B(R⁸)_(z) where each R⁸ isa group that is reactive with a terminal —SH and/or a terminal —CH═CH₂group; each m is independently selected from a rational number from 0 to10; each n is independently selected from an integer from 1 to 60; eachp is independently selected from an integer from 2 to 6; each q isindependently selected from an integer from 0 to 5; each r isindependently selected from an integer from 2 to 10; and z is selectedfrom an integer from 3 to 6. In certain embodiments, B represents thecore of a polyfunctionalizing agent such as those disclosed in U.S. Pat.Nos. 4,366,307; 4,609,762; and 5,225,472, where a polyfunctionalizingagent refers to a compound having three or more moieties that arereactive with terminal —SH and/or a terminal —CH═CH₂ groups.

Polythioether polyols of Formula (6) and Formula (7) are generallydisclosed, for example, in U.S. Pat. No. 6,172,179, which isincorporated by reference in its entirety.

In certain embodiments, the polythioether polyol comprises a polyolselected from a polythioether polyol of Formula (20); a polythioetherpolyol of Formula (21), and a combination thereof:

R¹³—S—R¹—[—S—(CH₂)₂—O—[—R²—O-]_(m)(CH₂)₂—S—R¹-]_(n)—S—R¹³  (20)

{R¹³—S—R¹—[—S—(CH₂)₂—O—[—R²—O-]_(m)(CH₂)₂—S—R¹—]_(n)—O—}_(z)—B  (21)

where each R¹ is independently selected from C₂₋₆ alkanediyl, C₆₋₈cycloalkanediyl, C₆₋₁₀ alkanecycloalkanediyl,—[(—CH₂—)_(p)—X-]_(q)—(—CH₂—)_(r)—, and—[(—CH₂—)_(p)—X-]_(q)—(—CH₂—)_(r)—, wherein at least one —CH₂— group issubstituted with a methyl group; each R² is independently selected fromC₂₋₆ alkanediyl, C₆₋₈ cycloalkanediyl, C₆₋₁₀ alkanecycloalkanediyl, and—[(—CH₂—)_(p)—X-]_(q)—(—CH₂—)_(r)—; X is selected from —O—, —S— and—NR¹⁰—, where R¹⁰ is selected from hydrogen and methyl; Z represents thecore of an z-valent polyfunctionalizing agent B(R⁸)_(z) where each R⁸ isa group that is reactive with a terminal —SH and/or a terminal —CH═CH₂group; each m is independently selected from a rational number from 0 to10; each n is independently selected from an integer from 1 to 60; eachp is independently selected from an integer from 2 to 6; each q isindependently selected from an integer from 0 to 5; each r isindependently selected from an integer from 2 to 10; and z is selectedfrom an integer from 3 to 6; and each R¹³ is independently —(CH₂)₂—O—R⁵where each R⁵ is independently —(CH₂)_(t)—OH where each t isindependently selected from an integer from 1 to 6

In certain embodiments, B represents the core of a polyfunctionalizingagent such as those disclosed in U.S. Pat. Nos. 4,366,307; 4,609,762;and 5,225,472, where a polyfunctionalizing agent refers to a compoundhaving three or more moieties that are reactive with terminal —SH and/ora terminal —CH═CH₂ groups.

A polythioether polyol may comprise a polythioether diol, apolythioether triol, a polythioether polyol having a functionality from4 to 6, or a combination of any of the foregoing. In certainembodiments, a polythioether polyol comprises a combination of apolythioether diol and a polythioether triol. For example, in certainembodiments, a polythioether polyol comprises a combination of apolythioether diol of Formula (9):

HO—(CH₂)₄—O—(CH₂)₂-[—S-{(CH₂)₂—O}₂—(CH₂)₂—S-{(CH₂)₂—O}₃—(CH₂)₂-]_(n)—S-{(CH₂)₂—O}₂—(CH₂)₂—S—(CH₂)₂—O—(CH₂)₄—OH  (9)

and a polythioether triol of Formula (10):

where each A is a moiety of Formula (11):

HO—(CH₂)₄—O—(CH₂)₂—S-{(CH₂)₂—O}₂—(CH₂)₂—S—[—{(CH₂)₂—O}₃—(CH₂)₂—S-{(CH₂)₂—O}₂—(CH₂)₂—S-]_(n)—(CH₂)₂—  (11)

where n is selected from an integer from 1 to 60, and in certainembodiments, an integer from 7 to 30.

In certain embodiments, polythioether polyols comprise a structurehaving Formula (12):

—R¹—[—S—(CH₂)₂—O—[—R²—O-]_(m)—(CH₂)₂—S—R¹—]_(n)—  (12)

where:

each R¹ is independently selected from C₂₋₆ alkanediyl, C₆₋₈cycloalkanediyl, C₆₋₁₀ alkanecycloalkanediyl,—[(—CH₂—)_(p)—X-]_(q)—(—CH₂—)_(r), and—[(—CH₂—)_(p)—X-]_(q)—(—CH₂—)_(r), where at least one —CH₂— group issubstituted with a methyl group;

each R² is independently selected from C₂₋₆ alkanediyl, C₆₋₈cycloalkanediyl, C₆₋₁₀ alkanecycloalkanediyl, and—[(—CH₂—)_(p)—X-]_(q)—(—CH₂—)_(r)—;

each X is selected from —O—, —S— and —NR¹⁰—, wherein R¹⁰ is selectedfrom hydrogen and methyl;

each m is independently selected from a rational number from 0 to 10;

each n is independently selected from an integer from 1 to 60;

each p is independently selected from an integer from 2 to 6;

each q is independently selected from an integer from 0 to 5; and

each r is independently selected from an integer from 2 to 10.

In certain embodiments, a polythioether polyol comprises a polythioetherpolyol of Formula (13):

R⁴—[R³]_(y)-A-[R³]_(y)—R⁴  (13)

where:

A has the structure of Formula (12);

each y is independently selected from 0 and 1;

each R³ is a single bond where y is 0; or each R³ is independently—S—(CH₂)₂-[—O—R²-]_(m) O— where y is 1;

each R⁴ is independently —S—(CH₂)_(2+s)—O—R⁵ where y is 0; or each R⁴ isindependently —(CH₂)₂—S—R⁵ where y is 1;

each m is independently selected from a rational number from 0 to 10;

each s is independently selected from an integer from 0 to 10; and

each R⁵ is independently —(CH₂)_(t)—OH where each t is independentlyselected from an integer from 1 to 6.

In certain embodiments, a polythioether polyol comprises a polythioetherpolyol of Formula (14):

B-(A-[R³]_(y)—R⁴)_(z)  (14)

where:

each A independently has the structure of Formula (12);

each y is independently selected from 0 and 1;

each R³ is a single bond where y is 0; or each R³ is independently—S—(CH₂)₂-[—O—R²-]_(m) O— where y is 1;

each R⁴ is independently —S—(CH₂)_(2+s)—O—R⁵ where y is 0; or each R⁴ isindependently —(CH₂)₂—S—R⁵ where y is 1;

each R⁵ is independently —(CH₂)_(t)—OH where each t is independentlyselected from an integer from 1 to 6;

each m is independently selected from a rational number from 0 to 10;

each s is independently selected from an integer from 0 to 10;

z is independently selected from an integer from 3 to 6; and

B is a z-valent residue of a polyfunctionalizing agent B(R⁸)_(z) whereeach R⁸ is a moiety that is reactive with a terminal —SH and/or aterminal —CH═CH₂ group.

In certain embodiments, a polythioether polyol comprises a combinationof a polythioether polyol of Formula (13) and a polythioether polyol ofFormula (14).

In certain embodiments, a polythioether polyol comprises the reactionproducts of a thiol-terminated polythioether and a hydroxyl-functionalvinyl ether. The preparation of thiol-terminated polythioethers isdisclosed, for example, in U.S. Pat. No. 6,172,179.

In certain embodiments, a thiol-terminated sulfur-containing prepolymercomprises a thiol-terminated polythioether comprising a backbonecomprising the structure of Formula (22):

—R¹—[—S—(CH₂)₂—O—[—R²—O-]_(m)—(CH₂)₂—S—R¹]_(n)—  (22)

wherein,

each R¹ is independently selected from a C₂₋₁₀ n-alkanediyl group, aC₃₋₆ branched alkanediyl group, a C₆₋₈ cycloalkanediyl group, a C₆₋₁₀alkanecycloalkanediyl group, a heterocyclic group, a—[(—CHR³—)_(p)—X-]_(q)—(CHR³)_(r)— group, wherein each R³ is selectedfrom hydrogen and methyl;

each R² is independently selected from a C₂₋₁₀ n-alkanediyl group, aC₃₋₆ branched alkanediyl group, a C₆₋₈ cycloalkanediyl group, a C₆₋₁₄alkanecycloalkanediyl group, a heterocyclic group, and a—[(—CH₂—)_(p)—X-]_(q)—(CH₂)_(r)— group;

each X is independently selected from O, S, —NH—, and —N(—CH₃)—;

m ranges from 0 to 50;

n is an integer ranging from 1 to 60;

p is an integer ranging from 2 to 6;

q is an integer ranging from 1 to 5; and

r is an integer ranging from 2 to 10.

In certain embodiments of a prepolymer of Formula (22), R¹ is—[—(CHR³)_(s)—X-]_(q)—(CHR³)_(r)— wherein each X is independentlyselected from —O— and —S—. In certain embodiments wherein R¹ is—[—(CHR³)_(s)—X-]_(q)—(CHR³)_(r-), each X is —O— and in certainembodiments, each X is —S—.

In certain embodiments of a prepolymer of Formula (22), R¹ is—[—(CH₂)_(s)—X-]_(q)—(CH₂)_(r)— wherein each X is independently selectedfrom —O— and —S—. In certain embodiments wherein R¹ is—[—(CH₂)_(s)—X-]_(q)—(CH₂)_(r)—, each X is —O— and in certainembodiments, each X is —S—.

In certain embodiments, R¹ in Formula (22) is—[(—CH₂—)_(p)—X-]_(q)—(CH₂)_(r)—, where p is 2, X is O, q is 2, r is 2,R² is ethanediyl, m is 2, and n is 9.

In certain embodiments of Formula (22), each R¹ is derived fromdimercaptodioxaoctane (DMDO) and in certain embodiments, each R¹ isderived from dimercaptodiethylsulfide (DMDS).

In certain embodiments of Formula (22), each m is independently aninteger from 1 to 3. In certain embodiments, each m is the same and is1, 2, and in certain embodiments, 3.

In certain embodiments of Formula (22), n is an integer from 1 to 30, aninteger from 1 to 20, an integer from 1 to 10, and in certainembodiments, and an integer from 1 to 5. In addition, in certainembodiments, n may be any integer from 1 to 60.

In certain embodiments of Formula (22), each p is independently selectedfrom 2, 3, 4, 5, and 6. In certain embodiments, each p is the same andis 2, 3, 4, 5, or 6.

In certain embodiments, a thiol-terminated sulfur-containing prepolymercomprises a thiol-terminated polythioether prepolymer. Examples ofthiol-terminated polythioether prepolymers are disclosed, for example,in U.S. Pat. No. 6,172,179. In certain embodiments, a thiol-functionalpolythioether adduct comprises Permapol® P3.1E, available fromPRC-DeSoto International Inc., Sylmar, Calif.

In certain embodiments, a thiol-terminated sulfur-containing prepolymercomprises a thiol-terminated polythioether prepolymer selected from athiol-terminated polythioether prepolymer of Formula (23a), athiol-terminated polythioether prepolymer of Formula (23b), and acombination thereof:

HS—R¹—[—S—(CH₂)_(p)—O—(R²—O)_(m)—(CH₂)₂—S—R¹—]_(n)—SH  (23a)

{HS—R¹—[—S—(CH₂)_(p)O—(R²—O)_(m)(CH₂)₂—S—R¹-]_(n)—S—V′-}_(z)B  (23b)

wherein,

each R¹ independently is selected from C₂₋₁₀ alkanediyl, C₆₋₈cycloalkanediyl, C₆₋₁₄ alkanecycloalkanediyl, C₅₋₈heterocycloalkanediyl, and —[(—CHR³—)_(s)—X-]_(q)—(—CHR³—)_(r)—,wherein,

-   -   s is an integer from 2 to 6;    -   q is an integer from 1 to 5;    -   r is an integer from 2 to 10;    -   each R³ is independently selected from hydrogen and methyl; and

each X is independently selected from —O—, —S—, —NH—, and —N(—CH₃)—;

-   -   each R² is independently selected from C₁₋₁₀ alkanediyl, C₆₋₈        cycloalkanediyl, C₆₋₁₄ alkanecycloalkanediyl, and        —[(—CHR³—)_(s)—X-]_(q)—(—CHR³—)_(r)—, wherein s, q, r, R³, and X        are as defined as for R¹;

m is an integer from 0 to 50;

n is an integer from 1 to 60;

p is an integer from 2 to 6;

B represents a core of a z-valent, polyfunctionalizing agent B(—V)_(z)wherein,

-   -   z is an integer from 3 to 6; and    -   each V is a moiety comprising a terminal group reactive with a        thiol; and    -   each —V′— is derived from the reaction of —V with a thiol.

In certain embodiments, Formula (23a) and in Formula (23b), R¹ is—[(—CH₂—)_(p)—X-]_(q)—(CH₂)_(r)—, where p is 2, X is —O—, q is 2, r is2, R² is ethanediyl, m is 2, and n is 9.

In certain embodiments of Formula (23a) and Formula (23b), R¹ isselected from C₂₋₆ alkanediyl and —[—(CHR³)_(s)—X-]_(q)—(CHR³)_(r)—.

In certain embodiments of Formula (23a) and Formula (23b), R¹ is—[—(CHR³)_(s)—X-]_(q)—(CHR³)_(r)—, and in certain embodiments X is —O—and in certain embodiments, X is —S—.

In certain embodiments of Formula (23a) and Formula (23b), where R¹ is—[—(CHR³)_(s)—X-]_(q)—(CHR³)_(r)—, p is 2, r is 2, q is 1, and X is —S—;in certain embodiments, wherein p is 2, q is 2, r is 2, and X is —O—;and in certain embodiments, p is 2, r is 2, q is 1, and X is —O—.

In certain embodiments of Formula (23a and Formula (23b), where R¹ is—[—(CHR³)_(s)—X-]_(q)—(CHR³)_(r)—, each R³ is hydrogen, and in certainembodiments, at least one R³ is methyl.

In certain embodiments of Formula (23a) and Formula (23b), each R¹ isthe same, and in certain embodiments, at least one R¹ is different.

For example, in certain embodiments, a thiol-terminated polythioethermay be prepared by reacting (n+1) moles of one or more dithiols ofFormula (15):

HS—R¹—SH  (15)

where R¹ is defined as for Formula (12); with (n) moles one or moredivinyl ethers of Formula (16):

CH₂═CH—O—[—R²—O-]_(m)CH═CH₂  (16)

where R² and m are defined as for Formula (12); in the presence of asuitable catalyst. In certain embodiments, a thiol-terminatedpolythioether comprises the products of the foregoing reaction.

Compounds of Formula (15) are dithiols. In certain embodiments of adithiol, R¹ is a C₂₋₆ n-alkanediyl such as, 1,2-ethanedithiol,1,3-propanedithiol, 1,4-butanedithiol, 1,5-pentanedithiol, and1,6-hexanedithiol.

In certain embodiments of a dithiol of Formula (15), R¹ is a C₃₋₆branched alkanediyl group, having one or more pendent groups which canbe, for example, methyl or ethyl groups. In certain embodiments of adithiol in which R¹ is branched alkanediyl, the dithiol is selected from1,2-propanedithiol, 1,3-butanedithiol, 2,3-butanedithiol,1,3-pentanedithiol, and 1,3-dithio-3-methylbutane. Other suitabledithiols include compounds of Formula (15) in which R¹ is a C₆₋₈cycloalkanediyl or C₆₋₁₀ alkylcycloalkanediyl, for example,dipentenedimercaptan or ethylcyclohexyldithiol (ECHDT).

In certain embodiments, a dithiol includes one or more heteroatomsubstituents in the carbon backbone, for example, dithiols in which X isa heteroatom such as O, S or another bivalent heteroatom radical; asecondary or tertiary amine group, i.e., —NR⁶—, where R⁶ is hydrogen ormethyl; or another substituted trivalent heteroatom. In certainembodiments of a dithiol, X is O or S, such that R¹ is, for example,—[(—CH₂—)_(p)—O-]_(q)—(—CH₂—)_(r)— or—[(—CH₂—)_(p)—S-]_(q)—(—CH₂—)_(r)—. In certain embodiments of a dithiol,p and r are the same, and in certain embodiments, each of p and r is 2.In certain embodiments, a dithiol is selected fromdimercaptodiethylsulfide (DMDS), dimercaptodioxaoctane (DMDO), and1,5-dithia-3-oxapentane. In certain embodiments of a dithiol, thedithiol includes heteroatom substituents in the carbon backbone andincludes a pendent alkyl group, such as a methyl group. In certainembodiments, a dithiol is selected from methyl-substituted DMDS, such asHS—CH₂CH(CH₃)—S—CH₂CH₂—SH, HS—CH(CH₃)CH₂—S—CH₂CH₂—SH, anddimethyl-substituted DMDS such as HS—CH₂CH(CH₃)—S—CH(CH₃)CH₂—SH andHS—CH(CH₃)CH₂—S—CH₂CH(CH₃)—SH.

Compounds of Formula (16) are divinyl ethers. Divinyl ether itself (m is0) can be used. In certain embodiments, divinyl ethers include compoundshaving at least one oxyalkanediyl group, and in certain embodiments,from 1 to 4 oxyalkanediyl groups (i.e., compounds in which m is selectedfrom an integer from 1 to 4). In certain embodiments of a compound ofFormula (16), m is selected from an integer from 2 to 4. It is alsopossible to employ commercially available divinyl ether mixtures inproducing polythioethers according to the present disclosure. Suchmixtures may be characterized by a non-integral average value for thenumber of alkoxy units per molecule. Thus, m in Formula (16) may alsotake on non-integral, rational values between 0 and 10, in certainembodiments, between 1 and 10, in certain embodiments, between 1 and 4,and in certain embodiments, between 2 and 4.

Examples of suitable divinyl ethers include compounds in which R² isC₂₋₆ alkanediyl such as, for example, ethylene glycol divinyl ether(EG-DVE); butanediol divinyl ether (BD-DVE); hexanediol divinyl ether(HD-DVE); diethylene glycol divinyl ether (DEG-DVE)); triethylene glycoldivinyl ether; and tetraethylene glycol divinyl ether. Suitable divinylether blends include PLURIOL®-type blends such as PLURIOL® E-200 divinylether (commercially available from BASF), and DPE polymeric blends suchas DPE-2 and DPE-3 (commercially available from International SpecialtyProducts, Wayne, N.J.). In certain embodiments, a divinyl ether ofFormula (16) is selected from DEG-DVE and PLURIOL® E-200. Divinyl ethersin which R² is C₂₋₆ branched alkanediyl may be prepared by reacting apolyhydroxy compound with acetylene. Examples of these divinyl ethersinclude compounds in which R² is an alkyl-substituted methylene groupsuch as —CH(CH₃)— and an alkyl-substituted ethylene such as—CH₂CH(CH₃)—.

In certain embodiments, a thiol-terminated polythioether may be preparedby reacting (n+1) moles of a compound of one or more divinyl ethers ofFormula (16); and (n) moles of one or more dithiols of Formula (15); inthe presence of appropriate suitable catalyst. In certain embodiments, athiol-terminated polythioether comprises the products of the foregoingreaction.

In certain embodiments, a thiol-terminated polythioether may be preparedby reacting (n+1) moles of a compound of one or more dithiols of Formula(15); and (n) moles of one or more divinyl ethers of Formula (16); inthe presence of appropriate suitable catalyst. In certain embodiments, athiol-terminated polythioether comprises the products of the foregoingreaction.

Polyfunctional thiol-terminated polythioethers may be prepared, forexample, by reacting (n+1) moles of one or more dithiols of Formula(15); (n) moles of one or more divinyl ethers of Formula (16); and oneor more z-valent polyfunctionalizing agents; in the presence of asuitable catalyst. In certain embodiments, a polyfunctionalthiol-terminated polythioether comprises the products of the foregoingreaction.

A polyfunctionalizing agent is a compound having more than two moieties,such as from 3 to 6 moieties, that are reactive with terminal —SH and/orterminal —CH═CH₂ groups. A polyfunctionalizing agent may be representedby Formula (17):

B—(R)_(z)  (17)

where each R⁸ is independently selected from a group that is reactivewith terminal —SH and/or terminal —CH═CH₂ groups, and z is selected froman integer from 3 to 6. Examples of polyfunctionalizing agents includetriallylcyanurate (TAC) and 1,2,3-propanetrithiol. Other suitablepolyfunctionalizing agents include trimethylolpropane trivinyl ether,and the polythiols disclosed in U.S. Pat. Nos. 4,366,307, 4,609,762,5,225,472, and 6,172,179.

In certain embodiments, polyfunctional thiol-terminated polythioethersmay also be prepared by reacting (n) moles of one or more dithiols ofFormula (15); (n+1) moles of one or more divinyl ethers of Formula (16);and one or more z-valent polyfunctionalizing agent; in the presence of asuitable catalyst. In certain embodiments, a thiol-terminatedpolythioether comprises the products of the foregoing reaction.

In certain embodiments, thiol-terminated polythioether may be preparedby reacting one or more dithiols of Formula (15); one or more divinylethers of Formula (16); and one or more polyfunctionalizing agents; inthe presence of a suitable catalyst, at a temperature, for example, from30° C. to 120° C. for 2 hours to 24 hours. In certain embodiments, athiol-terminated polythioether comprises the products of the foregoingreaction.

A thiol-terminated polythioether may then be reacted with ahydroxy-functional vinyl ether to provide a polythioether polyol.Examples of suitable hydroxy-functional vinyl ethers useful for reactingwith thiol-terminated polythioethers include triethylene glycolmonovinyl ether, 1,4-cyclohexane dimethylol monovinyl ether,1-methyl-3-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, and acombination of any of the foregoing. In certain embodiments, thehydroxy-functional vinyl ether is 4-hydroxybutyl vinyl ether. In certainembodiments, a thiol-terminated polythioether may be reacted with astoichiometric amount of hydroxy-functional vinyl ether such as4-hydroxybutyl vinyl ether. In certain embodiments, a polythioetherpolyol may be prepared by reacting Permapol® 3.1E with ahydroxy-functional vinyl ether such as 4-hydroxybutyl vinyl ether.

In certain embodiments, the polythioether polyol comprises from 60% to95% of a polythioether diol, and from 5% to 40% of a polythioethertriol, where percent refers to molar percent. In certain embodiments,the polythioether polyol comprises from 70% to 90% of a polythioetherdiol, and from 10% to 30% of a polythioether triol, where percent refersto molar percent. In certain embodiments, the polythioether polyolcomprises from 75% to 85% of a polythioether diol, and from 15% to 25%of a polythioether triol, where percent refers to molar percent. Incertain embodiments, the polythioether polyol comprises 80% of apolythioether diol, and from 20% of a polythioether triol, where percentrefers to molar percent.

In certain embodiments, the polythioether polyol comprises from 60% to95% of a polythioether diol of Formula (10), and from 5% to 40% of apolythioether triol of Formula (11), where percent refers to molarpercent. In certain embodiments, the polythioether polyol comprises from70% to 90% of a polythioether diol of Formula (10), and from 10% to 30%of a polythioether triol of Formula (11), where percent refers to molarpercent. In certain embodiments, the polythioether polyol comprises from75% to 85% of a polythioether diol of Formula (10), and from 15% to 25%of a polythioether triol of Formula (11), where percent refers to molarpercent. In certain embodiments, the polythioether polyol comprises 80%of a polythioether diol of Formula (10), and from 20% of a polythioethertriol of Formula (11), where percent refers to molar percent.

In certain embodiments, polythioether polyols provided by the presentdisclosure have a hydroxyl number from 10 to 100, from 20 to 100, from20 to 80, from 20 to 60, and in certain embodiments, from 20 to 40. Thehydroxyl number is the hydroxyl content of the polythioether polyol, andmay be determined, for example, by acetylating the hydroxyl groups andtitrating the resultant acid against potassium hydroxide. The hydroxylnumber is the weight of potassium hydroxide in milligrams that willneutralize the acid from one gram of the polythioether polyol.

In certain embodiments, polythioether polyols provided by the presentdisclosure have a number average molecular weight from 200 to 6,000Daltons, from 500 to 5,000 Daltons, from 1,000 to 4,000 Daltons, from1,500 to 3,500 Daltons, and in certain embodiments, from 2,000 Daltonsto 3,000 Daltons.

A polythioether polyol provided by the present disclosure may comprisefrom 50% to 90% of a polythioether diol and from 10% to 50% of apolythioether triol, and in certain embodiments from 70% to 90% of apolythioether diol and from 10% to 30% of a polythioether triol. Incertain embodiments, the polythioether polyol comprises a combination ofpolythioether polyols comprising from 70% to 90% of a polythioether diolof Formula (6) and from 10% to 30% of a polythioether triol of Formula(7), where wt % is based on the total functionality of the polythioetherpolyol. In certain embodiments, the polythioether polyol comprises acombination of polythioether polyols comprising from 70% to 90% of apolythioether diol of Formula (10) and from 10% to 30% of apolythioether triol of Formula (11), where wt % is based on the totalfunctionality of the polythioether polyol.

In certain embodiments, a polythioether polyol comprises a combinationof polythioether polyols and the average functionality of thecombination of polythioether polyols is from 2.1 to 4, from 3 to 4, from2.5 to 3.5, and in certain embodiments, from 2.1 to 2.5.

A polythioether-isocyanate prepolymer may be formed by reacting adiisocyanate with a polythioether polyol. In certain embodiments, themolar ratio of diisocyanate to polythioether polyol is greater than 2 to1, greater than 2.3 to 1, greater than 2.6 to 1, and in certainembodiments, greater than 3 to 1.

In certain embodiments, a polythioether-isocyanate prepolymer comprisesthe reaction products of a polythioether polyol and an aliphaticdiisocyanate.

Examples of suitable aliphatic diisocyanates for reacting with apolythioether polyol include, 1,6-hexamethylene diisocyanate,1,5-diisocyanato-2-methylpentane, methyl-2,6-diisocyanatohexanoate,bis(isocyanatomethyl)cyclohexane, 1,3-bis(isocyanatomethyl)cyclohexane,2,2,4-trimethylhexane 1,6-diisocyanate, 2,4,4-trimethylhexane1,6-diisocyanate, 2,5(6)-bis(isocyanatomethyl)cyclo[2.2.1.]heptane,1,3,3-trimethyl-1-(isocyanatomethyl)-5-isocyanatocyclohexane,1,8-diisocyanato-2,4-dimethyloctane,octahydro-4,7-methano-1H-indenedimethyl diisocyanate, and1,1′-methylenebis(4-isocyanatocyclohexane), and 4,4-methylenedicyclohexyl diisocyanate (H₁₂MDI).

Examples of suitable alicyclic aliphatic diisocyanates for reacting witha polythioether polyol include isophorone diisocyanate (IPDI),cyclohexane diisocyanate, methylcyclohexane diisocyanate,bis(isocyanatomethyl)cyclohexane, bis(isocyanatocyclohexyl)methane,bis(isocyanatocyclohexyl)-2,2-propane,bis(isocyanatocyclohexyl)-1,2-ethane,2-isocyanatomethyl-3-(3-isocyanatopropyl)-5-isocyanatomethyl-bicyclo[2.2.1]-heptane,2-isocyanatomethyl-3-(3-isocyanatopropyl)-6-isocyanatomethyl-bicyclo[2.2.1]-heptane,2-isocyanatomethyl-2-(3-isocyanatopropyl)-5-isocyanatomethyl-bicyclo[2.2.1]-heptane,2-isocyanatomethyl-2-(3-isocyanatopropyl)-6-isocyanatomethyl-bicyclo[2.2.1]-heptane,2-isocyanatomethyl-3-(3-isocyanatopropyl)-6-(2-isocyanatoethyl)-bicyclo[2.2.1]-heptane,2-isocyanatomethyl-2-(3-isocyanatopropyl)-5-(2-isocyanatoethyl)-bicyclo[2.2.1]-heptane,and2-isocyanatomethyl-2-(3-isocyanatopropyl)-6-(2-isocyanatoethyl)-bicyclo[2.2.1]-heptane.

In certain embodiments, a polythioether-isocyanate prepolymer comprisesthe reaction products of a polythioether polyol and an aliphaticdiisocyanate selected from IPDI, an HDI trimer, H₁₂MDI, and acombination of any of the foregoing.

In certain embodiments, a polythioether-isocyanate prepolymer comprisesthe reaction products of a polythioether polyol and 4,4′-methylenedicyclohexyl diisocyanate (H₁₂MDI). In certain embodiments, apolythioether-isocyanate prepolymer comprises the reaction products of a80 wt %/20 wt % combination of a polythioether diol of Formula (10) anda polythioether triol of Formula (11) and 4,4′-methylene dicyclohexyldiisocyanate (H₁₂MDI). In certain embodiments, apolythioether-isocyanate prepolymer comprises the reaction products ofthe 2:1 thio-ene adduct of 4-hydroxybutyl vinyl ether and a 80 wt %/20wt % combination of a polythioether diol of Formula (10) and apolythioether triol of Formula (11) and 4,4′-methylene dicyclohexyldiisocyanate (H₁₂MDI).

The first and second diisocyanates may be the same or different. Incertain embodiments, the first and second diisocyanates comprise one ormore aliphatic diisocyanates. In certain embodiments, the first andsecond diisocyanates are selected from IPDI, an HDI trimer, H₁₂MDI, anda combination of any of the foregoing. In certain embodiments, both thefirst diisocyanate and the second diisocyanate comprise 4,4′-methylenedicyclohexyl diisocyanate (H₁₂MDI).

Polythioether polyols may be prepared, for example, by reacting athiol-terminated polythioether with a hydroxy-functional vinyl ether toprovide a polythioether polyol. In certain embodiments, thethiol-terminated polythioether may comprise a thiol-terminatedpolythioether selected from a polythioether dithiol, a polythioethertrithiol, and a combination thereof. In certain embodiments, thethiol-terminated polythioether is any of the thiol-terminatedpolythioethers or combinations thereof disclosed in U.S. Pat. No.6,172,179, which is incorporated by reference in its entirety. Incertain embodiments, the thiol-terminated polythioether is a combinationof polythioether dithiols and polythioether trithiols, such as, forexample, Permapol® 3.1E (available from PRC-DeSoto International). Incertain embodiments, the thiol-terminated polythioether comprises thereaction product of one or more dithiols of Formula (15); one or moredivinyl ethers of Formula (16); and one or more polyfunctionalizingagents. The polythioether polyol may then be reacted with adiisocyanate, such as 4,4′-methylene dicyclohexyl diisocyanate (H₁₂MDI)to provide the polythioether-isocyanate prepolymer.

In certain embodiments, compositions provided by the present disclosurecomprise a catalyst such as an amine catalyst, an organometalliccatalyst, or an acid catalyst. Examples of suitable amine catalystsinclude, for example, triethylenediame (1,4-diazabicyclo[2.2.2]octane,DABCO), dimethylcyclohexylamine (DMCHA), dimethylethanolamine (DMEA),bis-(2-dimethylaminoethyl)ether, N-ethylmorpholine, triethylamine,1,8-diazabicyclo[5.4.0]undecene-7 (DBU), pentamethyldiethylenetriamine(PMDETA), benzyldimethylamine (BDMA),N,N,N′-trimethyl-N′-hydroxyethyl-bis(aminoethyl)ether, andN′-(3-(dimethylamino)propyl)-N,N-dimethyl-1,3-propanediamine. Examplesof suitable organometallic catalysts include, for example, mercury,lead, tin (dibutyltin dilaurate, dibutyltin oxide, dioctyltinmercaptide), and bismuth (bismuth octanoate). In certain embodiments,compositions provided by the present disclosure comprise a carboxylicacid catalyst such as, for example, formic acid (methanoic acid), aceticacid (ethanoic acid), propionic acid (propanoic acid), butyric acid(butanoic acid), valeric acid (pentanoic acid), caproic acid (hexanoicacid), enanthic acid (heptanoic acid), caprylic acid (heptanoic acid),pelargonic acid (nonanoic acid), capric acid (decanoic acid), or acombination of any of the foregoing. In certain embodiments,compositions provided by the present disclosure comprise pelargonicacid.

In certain embodiments, a composition comprises the reaction products ofreactants comprising a polyformal-isocyanate prepolymer comprising thereaction products of a polyformal polyol and a first aliphaticdiisocyanate; a polythioether-isocyanate prepolymer comprising thereaction products of a polythioether polyol and a second aliphaticdiisocyanate; and an aromatic diamine. In certain embodiments, the firstdiisocyanate and the second diisocyanate comprise H₁₂MDI, and in certainembodiments, the aromatic diamine comprises dimethylthiotoluenediamine.

In certain embodiments, a composition comprises the reaction products ofreactants comprising (a) a polythioether-isocyanate prepolymercomprising the reaction products of a polythioether polyol and H₁₂MDI,where the polythioether polyol comprises the reaction products ofPermapol® P3.1E and hydroxybutyl vinyl ether; and the molar ratio of theH₁₂MDI to the polythioether polyol is greater than 2 to 1; (b) apolyformal-isocyanate prepolymer comprising the reaction products of apolyformal diol of Formula (18) and H₁₂MDI;

wherein w is selected from an integer from 1 to 50; each R³ isethane-1,2-diyl; and the molar ratio of the H₁₂MDI to the polyformaldiol is greater than 2 to 1; and (c) an aromatic diamine selected fromdiethyltoluenediamine, dimethylthiotoluenediamine, and a combinationthereof.

In certain embodiments, a polythioether polyol may be prepared byreacting an isocyanate-terminated polythioether with a hydroxy vinylether such that there are a stoichiometric amount of thiol and alkenylgroups. In such embodiments, the thiol-terminated polythioether iscapped with terminal hydroxyl groups.

In certain embodiments of the above composition, w in a polyformal diolof Formula (18) may be from 7 to 30. In certain embodiments of the abovecomposition, the composition comprises from 70 wt % to 90 wt % of thepolythioether-isocyanate prepolymer and from 10 wt % to 30 wt % of thepolyformal-isocyanate prepolymer, where wt % is based on the totalweight percent of the prepolymers in the composition. In certainembodiments of the above composition, the composition comprises from 45wt % to 85 wt % of the polythioether-isocyanate prepolymer and from 15wt % to 55 wt % of the polyformal-isocyanate prepolymer, where wt % isbased on the total weight of the polythioether-isocyanate prepolymer andthe polyformal-isocyanate prepolymer in the composition. In certainembodiments of the above composition, the composition comprises from 55wt % to 75 wt % of the polythioether-isocyanate prepolymer and from 25wt % to 45 wt % of the polyformal-isocyanate prepolymer, where wt % isbased on the total weight of the polythioether-isocyanate prepolymer andthe polyformal-isocyanate prepolymer in the composition. In certainembodiments of the above composition, the aromatic diamine comprisesdimethylthiotoluenediamine such as ETHACURE® 300.

In certain embodiments, compositions provided by the present disclosurecomprise from 45 wt % to 85 wt % of a polythioether-isocyanateprepolymer and from 15 wt % to 55 wt % of a polyformal-isocyanateprepolymer, where wt % is based on the total weight of thepolythioether-isocyanate prepolymer and the polyformal-isocyanateprepolymer in the composition. In certain embodiments, compositionsprovided by the present disclosure comprise from 55 wt % to 75 wt % ofpolythioether-isocyanate prepolymer and from 25 wt % to 45 wt % of apolyformal-isocyanate prepolymer, where wt % is based on the totalweight of the polythioether-isocyanate prepolymer and thepolyformal-isocyanate prepolymer in the composition.

In certain embodiments, compositions provided by the present disclosurecomprise at least one filler, such as a filler that is effective inreducing the specific gravity of the composition. In certainembodiments, the specific gravity of a composition is from 0.8 to 1, 0.7to 0.9, from 0.75 to 0.85, and in certain embodiments, is 0.8. Suitablefillers for decreasing the specific gravity of the composition include,for example, hollow microspheres such as Expancel microspheres(available from AkzoNobel) or DUALITE® low density polymer microspheres(available from Henkel).

Composition Properties

In certain embodiments, polythioether-isocyanate prepolymers andpolyformal-isocyanate prepolymers provided by the present disclosure areliquid at room temperature. In certain embodiments, the prepolymers havea viscosity, at 100% solids, of no more than about 500 poise, such as 10to 300 poise or, in some cases, 100 to 200 poise, at a temperature of25° C. and a pressure of 760 mm Hg determined according to ASTM D-2849§79-90 using a Brookfield CAP 2000 viscometer.

Uses

Compositions provided by the present disclosure may be used as sealants,coatings, and/or electrical potting compositions. A sealant compositionrefers to a composition that is capable of producing a film that has theability to resist atmospheric conditions, such as moisture andtemperature and at least partially block the transmission of materials,such as water, fuel, and other liquid and gasses. In certainembodiments, sealant compositions of the present invention are useful,for example, as aerospace sealants and linings for fuel tanks.

In certain embodiments, compositions provided by the present disclosurecomprise from 10 wt % to 90 wt % of polythioether-isocyanate prepolymerand a polyformal-isocyanate prepolymer provided by the presentdisclosure, from 20 wt % to 80 wt %, from 30 wt % to 70 wt %, and incertain embodiments, from 40 wt % to 60 wt %, where wt % is based on thetotal weight of all non-volatile components of the composition (i.e.,the dry weight). In certain embodiments, compositions provided by thepresent disclosure comprise from 10 wt % to 90 wt % of apolythioether-isocyanate prepolymer and a polyformal-isocyanateprepolymer provided by the present disclosure, from 20 wt % to 90 wt %,from 30 wt % to 90 wt %, from 40 wt % to 90 wt %, from 50 wt % to 90 wt%, from 60 wt % to 90 wt %, from 70 wt % to 90 wt %, and in certainembodiments from 80 wt % to 90 wt %, where wt % is based on the totalweight of all non-volatile components of the composition (i.e., the dryweight).

Compositions provided by the present disclosure may comprise one or moredifferent types of filler. Suitable fillers include those commonly knownin the art, including inorganic fillers, such as carbon black andcalcium carbonate (CaCO₃), and lightweight fillers. Suitable lightweightfillers include, for example, those described in U.S. Pat. No.6,525,168. In certain embodiments, a composition includes 5 wt % to 60wt % of the filler or combination of fillers, 10 wt % to 50 wt %, and incertain embodiments, from 20 wt % to 40 wt %, based on the total dryweight of the composition.

As can be appreciated, polythioether-isocyanate prepolymers,polyformal-isocyanate prepolymers, amines, and fillers employed in acomposition, as well as any additives, may be selected so as to becompatible with each other.

Compositions provided by the present disclosure may include one or morecolorants, thixotropic agents, accelerators, retardants, adhesionpromoters, solvents, masking agents, or a combination of any of theforegoing.

As used herein, the term “colorant” means any substance that impartscolor and/or other opacity and/or other visual effect to thecomposition. A colorant can be of any suitable form, such as discreteparticles, dispersions, solutions, and/or flakes. A single colorant or acombination of two or more colorants can be used in a composition.

Examples of colorants include pigments, dyes and tints, such as thoseused in the paint industry and/or listed in the Dry Color ManufacturersAssociation (DCMA), as well as special effect compositions. A colorantmay include, for example, a finely divided solid powder that isinsoluble but wettable under the conditions of use. A colorant may beorganic or inorganic and may be agglomerated or non-agglomerated.Colorants may be incorporated into a composition by use of a grindvehicle, such as an acrylic grind vehicle. Examples of pigments and/orpigment compositions include carbazole dioxazine crude pigment, azo,monoazo, diazo, naphthol AS, salt type (flakes), benzimidazolone,isoindolinone, isoindoline, polycyclic phthalocyanine, quinacridone,perylene, perinone, diketopyrrolo pyrrole, thioindigo, anthraquinone,indanthrone, anthrapyrimidine, flavanthrone, pyranthrone, anthanthrone,dioxazine, triarylcarbonium, quinophthalone pigments, diketo pyrrolopyrrole red (DPPBO red), titanium dioxide, carbon black, andcombinations of any of the foregoing. Examples of dyes include thosethat are solvent- and/or aqueous-based such as phthalo green or blue,iron oxide, bismuth vanadate, anthraquinone, perylene, and quinacridone.Examples of tints include pigments dispersed in water-based orwater-miscible carriers such as AQUA-CHEM 896 commercially availablefrom Degussa, Inc., CHARISMA COLORANTS and MAXITONER INDUSTRIALCOLORANTS commercially available from Accurate Dispersions division ofEastman Chemical, Inc.

As noted above, a colorant may be in the form of a dispersion including,for example, a nanoparticle dispersion. Nanoparticle dispersions mayinclude one or more highly dispersed nanoparticle colorants and/orcolorant particles that produce a desired visible color and/or opacityand/or visual effect. Nanoparticle dispersions may include colorantssuch as pigments or dyes having a particle size of less than 150 nm,such as less than 70 nm, or less than 30 nm. Nanoparticles may beproduced by milling stock organic or inorganic pigments with grindingmedia having a particle size of less than 0.5 mm. Examples ofnanoparticle dispersions and methods for making them are disclosed inU.S. Pat. No. 6,875,800. Nanoparticle dispersions may also be producedby crystallization, precipitation, gas phase condensation, and/orchemical attrition (i.e., partial dissolution). To minimizere-agglomeration of nanoparticles within the coating, a dispersion ofresin-coated nanoparticles may be used. As used herein, a “dispersion ofresin-coated nanoparticles” refers to a continuous phase in which aredispersed discreet “composite microparticles” that comprise ananoparticle and a resin coating on the nanoparticle. Examples ofdispersions containing resin-coated nanoparticles and methods for makingthem are disclosed in U.S. Pat. No. 7,438,972.

Examples of special effect compositions that may be used in compositionsprovided by the present disclosure include pigments and/or compositionsthat produce one or more appearance effects such as reflectance,pearlescence, metallic sheen, phosphorescence, fluorescence,photochromism, photosensitivity, thermochromism, goniochromism, and/orcolor-change. Additional special effect compositions can provide otherperceivable properties, such as opacity or texture. In certainembodiments, special effect compositions may produce a color shift, suchthat the color of a composition changes when the coating is viewed atdifferent angles. Examples of color effect compositions are disclosed inU.S. Pat. No. 6,894,086. Additional color effect compositions mayinclude transparent coated mica and/or synthetic mica, coated silica,coated alumina, a transparent liquid crystal pigment, a liquid crystalcoating, and/or any composition wherein interference results from arefractive index differential within the material and not because of therefractive index differential between the surface of the material andthe air. In general, a colorant may comprise from 1 wt % to 65 wt % of acomposition, from 2 wt % to 50 wt %, such as from 3 wt % to 40 wt %, orfrom 5 wt % to 35 wt %, with weight percent based on the total dryweight of the composition.

Thixotropes, for example, silica, may be used in an amount from 0.1 wt %to 5 wt %, based on the total dry weight of the composition.

Accelerants may be present in an amount from 0.1 to 5 weight percent,based on the total weight of the composition. Examples of suitableaccelerants include 1,4-diazabicyclo[2.2.2]octane (DABCO®, Air Products,Chemical Additives Division) and DMP-30® (an accelerant compositionincluding 2,4,6-tris(dimethylaminomethyl)phenol).

Adhesion promoters, may be present in amount from 0.1 wt % to 15 wt % ofa composition, based on the total dry weight of the composition.Examples of adhesion promoters include phenolics, such as METHYLON®phenolic resin available from Occidental Chemicals, and organosilanes,such as epoxy, mercapto or amino functional silanes, such as SILQUEST®A-187 and SILQUEST® A-1100 available from Momentive PerformanceMaterials.

Masking agents, such as pine fragrance or other scents, which may beuseful in masking any low level odor of the composition, may be presentin an amount from 0.1 wt % to 1 wt %, based on the total dry weight ofthe composition.

In certain embodiments, compositions provided by the present disclosuremay comprise a plasticizer that may facilitate the use of prepolymershaving a higher glass transition temperature, T_(g), than wouldordinarily be useful in an aerospace sealant. For example, use of aplasticizer may effectively reduce the T_(g) of a composition, andthereby increase the low-temperature flexibility of the curedpolymerizable composition beyond that which would be expected on thebasis of the T_(g) of the prepolymers alone. Plasticizers suitable incertain embodiments of the compositions include, for example, phthalateesters, chlorinated paraffins, and hydrogenated terphenyls. Aplasticizer or combination of plasticizers may constitute from 1 wt % to40 wt % of a composition, or from 1 wt % to 10 wt % of a composition. Incertain embodiments, a composition may comprise one or more organicsolvents, such as isopropyl alcohol, in an amount, for example, from 0wt % to 15 wt %, from 0 wt % to 10 wt %, or from 0 wt % to 5 wt %, basedon the non-dry weight of the composition.

In certain embodiments, compositions provided by the present disclosureare substantially free or, in some cases, completely free, of anysolvent, such as an organic solvent or an aqueous solvent, i.e., water.Stated differently, in certain embodiments, compositions provided by thepresent disclosure are substantially 100% solids.

In certain embodiments, compositions, such as sealant compositions, maybe provided as multi-pack compositions, such as two-pack compositions,wherein one package comprises one or more prepolymers provided by thepresent disclosure and a second package comprises one or more aminecuring agents for the one or more prepolymers. Additives and/or othermaterials may be added to either package as desired or necessary. Thetwo packages may be combined and mixed prior to use. In certainembodiments, the pot life of the one or more mixed prepolymers andcuring agent is at least 30 minutes, at least 1 hour, at least 2 hours,and in certain embodiments, more than 2 hours, where pot life refers tothe period of time the mixed composition remains suitable for use as asealant after mixing.

Compositions provided by the present disclosure may be applied to any ofa variety of substrates. Examples of substrates to which the compositionmay be applied include metals such as titanium, stainless steel, andaluminum, which may be anodized, primed, organic-coated orchromate-coated; epoxy; urethane; graphite; fiberglass composite;KEVLAR®; acrylics; and polycarbonates.

Compositions provided by the present disclosure may be applied directlyonto the surface of a substrate or over an underlayer by any suitablecoating process known to those of ordinary skill in the art. In certainembodiments, such as for spray seal applications, a composition providedby the present disclosure may be sprayed onto a surface.

In certain embodiments, compositions provided by the present disclosureare fuel-resistant. As used herein, the term “fuel resistant” means thata composition, when applied to a substrate and cured, can provide acured product, such as a sealant, that exhibits a percent volume swellof not greater than 40%, in some cases not greater than 25%, in somecases not greater than 20%, in yet other cases not more than 10%, afterimmersion for one week at 140° F. (60° C.) and ambient pressure in JetReference Fluid (JRF) Type I according to methods similar to thosedescribed in ASTM D792 (American Society for Testing and Materials) orAMS 3269 (Aerospace Material Specification. Jet Reference Fluid JRF TypeI, as employed for determination of fuel resistance, has the followingcomposition: toluene: 28±1% by volume; cyclohexane (technical): 34±1% byvolume; isooctane: 38±1% by volume; and tertiary dibutyl disulfide:1±0.005% by volume (see AMS 2629, issued Jul. 1, 1989, §3.1.1 etc.,available from SAE (Society of Automotive Engineers)).

In certain embodiments, compositions provide a cured product, such as asealant, exhibiting an elongation of at least 100% and a tensilestrength of at least 400 psi when measured in accordance with theprocedure described in AMS 3279, §3.3.17.1, test procedure AS5127/1,§7.7.

In certain embodiments, compositions provide a cured product, such as asealant, exhibit a lap shear strength of greater than 200 psi and insome cases at least 400 psi when measured according to the proceduredescribed in SAE AS5127/1 paragraph 7.8.

In certain embodiments, a cured sealant comprising a compositionprovided by the present disclosure meets or exceeds the requirements foraerospace sealants as set forth in AMS 3277.

Furthermore, methods are provided for sealing an aperture utilizing acomposition provided by the present disclosure. These methods comprise,for example, applying a composition provided by the present disclosureto a surface to seal an aperture, and curing the composition. In certainembodiments, a composition may be cured under ambient conditions, whereambient conditions refers to a temperature from 20° C. to 25° C., andatmospheric humidity. In certain embodiments, a composition may be curedunder conditions encompassing a temperature from a 0° C. to 100° C. andhumidity from 0% RH to 100% RH. In certain embodiments, a compositionmay be cured at a higher temperature such as at least 30° C., at least40° C., and in certain embodiments, at least 50° C. In certainembodiments, a composition may be cured at room temperature, e.g., 25°C. In certain embodiments, a composition may be cured upon exposure toactinic radiation such as ultraviolet radiation. As will also beappreciated, the methods may be used to seal apertures on aerospacevehicles.

EXAMPLES

Embodiments provided by the present disclosure are further illustratedby reference to the following examples, which describe the synthesis,properties, and uses of polythioether polyols and prepolymers thereof,polyformal polyols and prepolymers thereof, and compositions of any ofthe foregoing. It will be apparent to those skilled in the art that manymodifications, both to materials, and methods, may be practiced withoutdeparting from the scope of the disclosure.

Example 1 Polyformal Polyol

Thiodiglycol (1,833 g), paraformaldehyde (95% purity) (360 g),AMBERLYST™15 (319 g, available from Dow Chemical Company), and toluene(1,000 mL) were charged into a 5-L, 4-neck, round-bottom flask. Theflask was equipped with a heating mantle, thermocouple, temperaturecontroller, and a Dean-Stark adapter fitted with a reflux condenser,dropping funnel, and an inlet for nitrogen positive pressure. Thereactants were stirred under nitrogen, heated to 118° C., and maintainedat 118° C. for ca. 7 h. During this period, collected water wasperiodically removed from the Dean-Stark adapter. The reaction mixturewas then cooled to room temperature and filtered through acoarse-fritted Buchner funnel (600 mL volume) with a 9.0 cm diameterWhatman GF/A filter paper over the frit. The flask and filter cake werewashed with 500 mL toluene. A filtrate was obtained. The filtrate wasthen dried in vacuo using a 2-L round bottomed flask (rotary evaporator,7 torr final vacuum, 90° C. water bath) to provide a yellow, viscouspolymer (1,456 g). The resulting thiodiglycol polyformal polyol had ahydroxyl number of 34.5 and a viscosity of 92 poise.

Example 2 H₁₂MDI-Terminated Polyformal-Isocyanate Prepolymer

The thiodiglycol polyformal polyol of Example 1 (450 g) was charged intoa 1,000-mL, 4-neck, round-bottom flask. The flask was equipped with amantle, thermocouple, temperature controller, an inlet for providingnitrogen positive pressure, and a mechanical stirrer (PTFE paddle andbearing). The polyformal polyol was stirred at ca. 200 rpm and heated to76.6° C. (170° F.), followed by the addition of DESMODUR® W (H₁₂MDI)(99.5 g) and a 0.01% solution of dibutyltin dilaurate dissolved inmethyl ethyl ketone (5.50 g). The reaction mixture was maintained at76.6° C. for 7 h and then cooled to room temperature. A 1% solution ofbenzyl chloride dissolved in methyl ethyl ketone (5.50 g) was then addedto the reaction mixture. The resulting thiodiglycolpolyformal-isocyanate prepolymer had an isocyanate content of 3.73% anda viscosity of 356 poise.

Example 3 HDI-Uretidione-Terminated Polyformal-Isocyanate Prepolymer

The thiodiglycol polyformal polyol of Example 1 (101 g) was charged intoa 500-mL, 4-neck, round-bottom flask. The flask was equipped with amantle, thermocouple, temperature controller, an inlet for providingnitrogen positive pressure, and a mechanical stirrer (PTFE paddle andbearing). The polyformal polyol was stirred at ca. 200 rpm and heated to76.6° C. (170° F.), followed by the addition of DESMODUR® XP-2730(HDI-uretidione aliphatic polyisocyanate) (33.4 g) and a 0.01% solutionof dibutyltin dilaurate dissolved in methyl ethyl ketone (1.4 g). Thereaction mixture was maintained at 76.6° C. for ca. 7 h and then cooledto room temperature. A 1% solution of benzyl chloride dissolved inmethyl ethyl ketone (1.4 g) was then added to the reaction mixture. Theresulting prepolymer had an isocyanate content of 3.41% and a viscosityof 695 poise.

Example 4 HDI-Uretidione-Terminated Polyformal-Isocyanate Prepolymer

The thiodiglycol polyformal polyol of Example 1 (400 g) was charged intoa 1,000-mL, 4-neck, round-bottom flask. The flask was equipped with amantle, thermocouple, temperature controller, an inlet for providingnitrogen positive pressure, and a mechanical stirrer (PTFE paddle andbearing). The polyformal polyol was stirred at ca. 200 rpm and heated to76.6° C. (170° F.), followed by the addition of DESMODUR® N-3400 (137 g)and a 0.01% solution of dibutyltin dilaurate dissolved in methyl ethylketone (5.50 g). The reaction mixture was maintained at 76.6° C. for ca.7 h and then cooled to room temperature. A 1% solution of benzylchloride dissolved in methyl ethyl ketone (5.5 g) was then added to thereaction mixture. The resulting thiodiglycol polyformal-isocyanateprepolymer had an isocyanate content of 3.31% and a viscosity of 697poise.

Example 5 HDI-Uretidione-Terminated Polyformal-Isocyanate Prepolymer

The thiodiglycol polyformal polyol of Example 1 (504 g) was charged intoa 1,000-mL, 4-neck, round-bottom flask. The flask was equipped with amantle, thermocouple, temperature controller, an inlet for providingnitrogen positive pressure, and a mechanical stirrer (PTFE paddle andbearing). The polyformal polyol was stirred at ca. 200 rpm and heated to76.6° C. (170° F.), followed by the addition of DESMODUR® N-3400 (521 g)and a 0.01% solution of dibutyltin dilaurate dissolved in methyl ethylketone (10.3 g). The reaction mixture was maintained at 76.6° C. for ca.7 h and then cooled to room temperature. A 1% solution of benzylchloride dissolved in methyl ethyl ketone (10.4 g) was then added to thereaction mixture. The resulting thiodiglycol polyformal-isocyanateprepolymer had an isocyanate content of 8.94% and a viscosity of 46poise.

Example 6 Isophorone-Terminated Polyformal-Isocyanate Prepolymer

The thiodiglycol polyformal polyol of Example 1 (325 g) was charged intoa 500-mL, 4-neck, round-bottom flask. The flask was equipped with amantle, thermocouple, temperature controller, an inlet for providingnitrogen positive pressure, and a mechanical stirrer (PTFE paddle andbearing). The polyformal polyol was stirred at ca. 200 rpm and heated to76.6° C. (170° F.), followed by the addition of DESMODUR® I (62.5 g)(IPDI) and a 0.01% solution of dibutyltin dilaurate dissolved in methylethyl ketone (4 g). The reaction mixture was maintained at 76.6° C. forca. 7 h and then cooled to room temperature. A 1% solution of benzylchloride dissolved in methyl ethyl ketone (4 g) was then added to thereaction mixture. The resulting thiodiglycol polyformal-isocyanateprepolymer had an isocyanate content of 3.51% and a viscosity of 229poise.

Example 7 H₁₂MDI-Terminated Polythioether-Isocyanate Prepolymer

A thiol-terminated polythioether was prepared according to Example 1 ofU.S. Pat. No. 6,172,179. In a 2-L flask, 524.8 g (3.32 mol) ofdiethylene glycol divinyl ether (DEG-DVE) and 706.7 g (3.87 mol) ofdimercaptodioxaoctane (DMDO) were mixed with 19.7 g (0.08 mol) oftriallylcyanurate (TAC) and heated to 77° C. To the reaction mixture wasadded 4.6 g (0.024 mol) of an azobisnitrile free radical catalyst(VAZO®67, 2,2′-azobis(2-methylbutyronitrile)). The reaction proceededsubstantially to completion after 2 to afford 1,250 g (0.39 mol, yield100%) of a liquid thiol-terminated polythioether resin having a T_(g) of−68° C. and a viscosity of 65 poise. The resin was faintly yellow andhad low odor.

A 1-liter, 4-neck round-bottomed flask was fitted with a mantle,thermocouple, temperature controller, nitrogen line, mechanical stirrerand dropping funnel. The flask was charged with a thiol-terminatedpolythioether (652.30 g) prepared according to Example 1 of U.S. Pat.No. 6,172,179 (see previous paragraph). The flask was heated to 71° C.under nitrogen and stirred at 300 rpm. A mixture of 4-hydroxybutyl vinylether (47.40 g) and Vazo-67 (1.19 g) was added to the flask in 1 hourvia a dropping funnel. The reaction mixture was maintained at 71° C. forca. 41 hours, at which time the reaction was complete. After this, thereaction apparatus was then fitted with a vacuum line and the productheated to 94° C. Heating was continued for 1.3 hours under vacuum.Following vacuum treatment, a pale yellow, viscous polythioether polyol(678.80 g) was obtained. The polythioether polyol had a hydroxyl numberof 31.8 and a viscosity of 77 Poise.

The polythioether polyol (300.03 g) was then charged into a 500-mL,4-neck, round-bottom flask. The flask was equipped with a mantle,thermocouple, temperature controller, an inlet for providing nitrogenpositive pressure, and a mechanical stirrer (PTFE paddle and bearing).The polythioether polyol was stirred at ca. 200 rpm and heated to 76.6°C. (170° F.), followed by the addition of DESMODUR® W (H₁₂MDI) (82.90 g)and a 0.01% solution of dibutyltin dilaurate dissolved in methyl ethylketone (3.90 g). The reaction mixture was maintained at 76.6° C. for ca.7 h and then cooled to room temperature. A 1% solution of benzylchloride dissolved in methyl ethyl ketone (3.80 g) was then added to thereaction mixture. The resulting H₁₂MDI-terminated polythioetherprepolymer had an isocyanate content of 4.47% and a viscosity of 282poise.

Comparative Example 8 H₁₂MDI-Terminated Poly(tetrahydrofuran) Prepolymer

TERATHANE® T-2000 (poly(tetrahydrofuran)) (400 g) was charged into in a1,000-mL, 3-neck, round-bottom flask. The flask was equipped with amantle, thermocouple, temperature controller, an inlet for providingnitrogen positive pressure, and a mechanical stirrer (PTFE paddle andbearing). TERATHANE® T-2000 was heated to 76.6° C. (170° F.) andstirred. DESMODUR® W (H₁₂MDI) (137.2 g) and a 0.01% solution ofdibutyltin dilaurate dissolved in methyl ethyl ketone (3.3 g) were addedto the flask. The mixture was reacted at 76.6° C. (170° F.) for ca. 6 h,at which time a 1% solution of benzyl chloride dissolved in methyl ethylketone (3.3 g) was added. The resulting poly(tetrahydrofuran)-isocyanateprepolymer had an isocyanate content of 4.67% and a viscosity of 479poise.

Comparative Example 9 H₁₂MDI-Terminated Polybutadiene Prepolymer

KRASOL® LBH-P 2000 (hydroxyl-terminated polybutadiene) (200 g) andKRASOL® HLBH-P 2000 (hydrogenated hydroxyl terminated polyolefin) (200g) were charged into in a 1,000-mL, 3-neck, round-bottom flask. Theflask was equipped with a mantle, thermocouple, temperature controller,an inlet for providing nitrogen positive pressure, and a mechanicalstirrer (PTFE paddle and bearing). The mixture was heated to 76.6° C.(170° F.) and stirred. DESMODUR® W (H₁₂MDI) (137.4 g) and a 0.01%solution of dibutyltin dilaurate dissolved in methyl ethyl ketone (5.4g) were added to the flask. The mixture was reacted at 76.6° C. (170°F.) for ca. 6 h, at which time a 1% solution of benzyl chloridedissolved in methyl ethyl ketone (5.4 g) was added to the reactionmixture. The resulting polybutadiene-isocyanate prepolymer had anisocyanate content of 5.34% and a viscosity of 892 poise.

Example 10 Cured Composition of H₁₂MDI-Terminated Polyformal Prepolymer

A 12×12 in² polyethylene sheet was placed on a flat 12×12×0.25 in³stainless steel plate. Four, 12×1×0.125 in³ spacers were placed on theedges of the polyethylene sheet. The polyformal-isocyanate prepolymer ofExample 2 (90 g), pelargonic acid (1.1 g), and ETHACURE® 300 (8.15 g,Albemarle Corporation) were added to a plastic container. The materialswere mixed first by hand, and then for 60 seconds at 2,300 rpm in amixer (DAC 600 FVZ).

The mixed composition was poured uniformly onto the polyethylene sheetbetween the spacers. A second 12×12 in² polyethylene sheet was placed onthe top of the composition such that the second polyethylene sheet wasseparated from the first polyethylene sheet by the 0.125-in spacers. Asecond 12×12×0.125 in³ thick stainless steel plate was placed on top ofthe second polyethylene sheet. The composition, sandwiched between thetwo polyethylene sheets, was cured at room temperature for 48 h,followed by 24 h at 140° F. Finally, the polyethylene sheets wereremoved to provide a flat, ca. 0.125-in thick, cured polymer sheet.

The hardness, tensile strength and elongation, tear strength, volumeswell and water resistance of the polymer sheet are shown in Table 1.The hardness of cured polymer was measured according to ASTM D2240;tensile strength and elongation were measured according to ASTM D412;and tear strength was measured according to ASTM D624 Die C. Weight losswas measured according to SAE AS5127/1B §7.4, and volume swell wasmeasured according to SAE AS 5127/1B §7.5.

Example 11 Cured Composition of HDI-Uretidione-Terminated PolyformalPrepolymer

A cured polymer sheet was prepared as described in Example 10 for acomposition containing the polyformal-isocyanate prepolymer(HDI-uretidione terminated) of Example 3 (50 g), pelargonic acid (0.55g), and ETHACURE® 300 (4.13 g). The properties of the cured sealant arepresented in Table 1.

Example 12 Cured Composition of HDI-Uretidione-Terminated PolyformalPrepolymer

A cured polymer sheet was prepared as described in Example 10 for acomposition containing the polyformal-isocyanate prepolymer of Example 4(HDI-uretidione-terminated) (50 g), pelargonic acid (0.55 g), andETHACURE® 300 (4.02 g). The properties of the cured sealant arepresented in Table 1.

Example 13 Cured Composition of HDI/IPDI-Uretidione-TerminatedPolyformal Prepolymer

A cured polymer sheet was prepared as described in Example 10 for acomposition containing the HDI-uretidione-terminatedpolyformal-isocyanate prepolymer of Example 5 (12 g), theIPDI-terminated polyformal isocyanate prepolymer of Example 6 (48 g),pelargonic acid (0.72 g), and ETHACURE® 300 (6.69 g). The properties ofthe cured sealant are presented in Table 1.

Comparative Example 14 Cured Composition of H₁₂MDI-TerminatedPoly(tetrahydrofuran)

A cured polymer sheet was prepared as described in Example 10 for acomposition containing the H₁₂MDI-terminated poly(tetrahydrofuran)prepolymer of Comparative Example 8 (50 g), pelargonic acid (0.6 g), andETHACURE® 300 (5.67 g). The properties of the cured sealant arepresented in Table 1.

Comparative Example 15 Cured Composition of Hydroxyl-TerminatedPolybutadiene/Hydrogenated Hydroxyl-Terminated Polyolefin Prepolymer

A cured polymer sheet was prepared as described in Example 10 for acomposition containing the H₁₂MDI-terminated hydroxyl-terminatedpolybutadiene/hydrogenated hydroxyl-terminated polyolefin prepolymer ofComparative Example 9 (50 g), pelargonic acid (0.6 g), and ETHACURE® 300(6.48 g). The properties of the cured sealant are presented in Table 1.

Example 16 Cured Compositions of H₁₂MDI-Terminated PolythioetherPrepolymer and H₁₂MDI-Terminated Polyformal Prepolymer

Cured polymer sheets were prepared as described in Example 10 forcompositions containing the polyformal-isocyanate prepolymer(H₁₂MDI-terminated) of Example 2 (32 g), the H₁₂MDI-terminatedpolythioether prepolymer of Example 7 (18 g), pelargonic acid (0.6 g),and ETHACURE® 300 (4.85 g). The properties of the cured sealant arepresented in Table 1.

Example 17 Cured Compositions Prepared Using Polyformal-IsocyanatePrepolymers, Polythioether-Isocyanate Prepolymers, and Amine CuringAgents

Cured compositions A-K were prepared according to Example 10.Compositions A-K contained the components as presented in Table 2 andthe properties of the cured compositions are presented in Tables 3-6. InTable 2, the isocyanate content refers to the percent isocyanate of theprepolymer and the isocyanate prepolymer weight refers to the weight ingrams of the isocyanate prepolymer reacted to provide the composition.N3400 refers to DESMODUR® N3400 and the H₁₂MDI was DESMODUR® W. To formthe polyformal-isocyanate prepolymers, a thiodiglycol polyformalprepared according to Example 1 was reacted with DESMODUR® N3400 orDESMODUR® W as described in Example 2. To form thepolythioether-isocyanate prepolymers, a polythioether polyol prepared asin Example 7, was reacted with DESMODUR® W as described in Example 7.

TABLE 1 Comparative Comparative Composition/Property Example 10 Example11 Example 12 Example 13 Example 14 Example 15 Example 16 Dry TensileStrength, psi 1170 640 616 1382 5062 2166 1011 Dry Elongation, % 466 14679 363 601 293 576 Dry Tear Strength, pli 178 84 75 144 438 206 172 DryHardness, Shore A 82 75 70 80 80 81 64 JRF Tensile Strength*, psi 918493 447 872 1674 263 731 JRF Elongation*, % 393 119 64 374 588 135 567JRF Tear Strength*, pli 158 32 25 76 11 16 117 JRF Hardness*, Shore A 7967 70 67 55 76 64 JRF Volume Swell,* % 24 14 14 17 116 185 16 WaterResistance** Excellent Excellent Excellent Excellent Excellent ExcellentExcellent *Tested following immersion of sample in Jet Reference FuelType I for 7 days at 140° F. **Tested following immersion of sample inwater for 7 days at 200° F.

TABLE 2 A B C D E F G H I J K Polyformal-isocyanate Prepolymer 1Isocyanate N-3400 H₁₂MDI H₁₂MDI H₁₂MDI H₁₂MDI Isocyanate 8.91 4.74 4.744.74 4.74 Content (%) Isocyanate 10.5 57.6 44.1 33 6.65 PrepolymerWeight (g) Polyformal-isocyanate Prepolymer 2 Isocyanate H₁₂MDI H₁₂MDIH₁₂MDI H₁₂MDI Isocyanate 2.67 3.73 3.73 3.73 Content (%) Isocyanate 32.444.1 32 18.35 Prepolymer Weight (g) Polythioether-isocyanate Prepolymer1 Isocyanate H₁₂MDI H₁₂MDI H₁₂MDI H₁₂MDI H₁₂MDI H₁₂MDI H₁₂MDI Isocyanate2.67 4.47 4.47 4.47 4.47 4.47 4.47 Content (%) Isocyanate 39.5 60 27 1811.25 27 60 Prepolymer Weight (g) Polythioether-isocyanate Prepolymer 2Isocyanate H₁₂MDI H₁₂MDI H₁₂MDI H₁₂MDI H₁₂MDI Isocyanate 3.63 3.63 3.633.63 3.63 Content (%) Isocyanate 33 60 17 13.75 33 Prepolymer Weight (g)ETHACURE ® 4.83 8.72 0.97 6.51 5.83 5.27 4.85 4.85 4.85 5.83 6.51 300(g) Pelargonic 0.6 1.08 0.72 0.72 0.72 0.66 0.6 0.6 0.6 0.72 0.72 Acid(g) Carbon Black (g) 0 0 0 0 0 0 0 0 0 7.2 7.2 DUALITE ™ (g) 0 0 0 0 0 00 0 0 6.8 6.8

TABLE 3 Test Property A B C Dry T/E^(†) (psi/%) 963/272 1227/5511233/612 Hardness (A) 78 82 75 Tear (pli) 165  308  177  Water** T/E(psi/%) 183/109  330/186  321/146 Hardness (A) 42 64 54 Tear (pli) 32 7653 VS %/WL %^(§) 4.2/3.5 2.7/2.3  3.6/2.5 JRF* T/E (psi/%) 731/2331072/593 1264/656 Hardness (A) 50 — 69 Tear (pli) 145  247  127  VS %/WL%^(§) 16.9/1.9  16.3/1.3 15.8/3.0 *Tested following immersion of samplein Jet Reference Fuel Type I for 7 days at 140° F. **Tested followingimmersion of sample in water for 7 days at 200° F. ^(†)Tensile strength(psi)/Elongation (%) ^(§)Volume Swell (%)/Weight Loss (%)

TABLE 4 Composition/Properties D E F Pot Life (hr)  >2  >2  >2 Dry T/E(psi/%); Hardness (Shore A) 2060/792, 73A 2023/866, 70A 1645/771, 70AJRF* T/E (psi/%); Hardness (Shore A) 1318/726, 66A 1343/795, 62A924/649, 62A Water** T/E (psi/%); Hardness (Shore A) 202/213, 50A150/245, 40A 116/266, 30A Dry Tear (pli) 270 263 217 JRF* Tear (pli) 136132 119 Water** Tear (pli)  59  44  37 JRF* VS %/WL % 20.7/2.6 21.0/2.722.4/1.9 Water** VS %/WL %  4.9/3.6  5.9/3.3  5.0/3.4 *Tested followingimmersion of sample in Jet Reference Fuel Type I for 7 days at 140° F.**Tested following immersion of sample in water for 7 days at 200° F.

TABLE 5 Composition/Properties G H I Dry T/E (psi/%); Hardness (Shore A)1825/770, 75A 1011/576, 70A 1440/743, 76A JRF* T/E (psi/%); Hardness(Shore A) 1143/533, 64A 731/567, 64A 916/584, 68A Water** T/E (psi/%);Hardness (Shore A) 263/322, 49A 203/147, 49A 236/216 50A Dry Tear (pli)259 172 155 JRF* Tear (pli) 139 117 139 Water** Tear (pli)  68  40  54JRF* VS %/WL % 18.8/2.7 16.1/3.3 16.5/3.11 Water** VS %/WL %  4.7/3.2 3.5/3.3 3.9/3.2 *Tested following immersion of sample in Jet ReferenceFuel Type I for 7 days at 140° F. **Tested following immersion of samplein water for 7 days at 200° F.

TABLE 6 Composition/Properties J K Specific Gravity 0.8 0.8 Dry T/E(psi/%); Hardness (Shore A) 873/461, 70A 765/321, 76A JRF* T/E (psi/%);Hardness (Shore A) 748/536, 60A 673/460, 64A Water** T/E (psi/%);Hardness (Shore A) 139/107, 50A 170/75, 54A Dry Tear (pli) 147 143 JRF*Tear (pli) 100 99 Water** Tear (pli) 40 44 JRF* VS %/WL % 11.6/1.613.0/1.5 Water** VS %/WL % −9.3/3.0 −9.6/2.8 Water 27 days 43A 63A*Tested following immersion of sample in Jet Reference Fuel Type I for 7days at 140° F. **Tested following immersion of sample in water for 7days at 200° F.

Example 18 Cured Compositions Prepared Using Isocyanate-terminatedPolythioether Prepolymers and Amine Curing Agents

A prepolymer formulation was prepared by mixing 99.1 g of theH12MDI-terminated polythioether prepolymer of Example 7 with 0.9 g ofparachlorobenzotrifluoride.

A curing agent had the composition shown in Table 8.

TABLE 8 Material % by Weight Bis(triethoxysilylpropyl)amine 33.14Bis(triethoxysilylpropyl)tetrasulfide 11.05 Deionized water 1.77Diphenylguanidine 0.18 Ethacure ® 100 43.10 Ethacure ® 300 10.77

To prepare the curing composition, the combined silanes were mixed at1700 rpm in a Hauschild jixer (FlackTek, Model: Speedmixer) for 15 sec.The mixture was heated in a 160° F. oven for 10 to 15 minutes with thelid closed and without venting. The deionized water was added and mixedinto the silanes at 1700 rpm for 30 sec in the Hauschild mixer.Diphenylguanidine was added and the composition mixed at 1700 rpm for 30sec in the Hauschild mixer. The mixture was equilibrated for 3 to 4hours with the lid loose while being gently mixed using a shaker. Theamines were then added and the composition mixed at 1700 for 30 secusing the Hauschild mixer. After the amines were incorporated, thecomposition was filtered through a 100 micron mesh.

A sealant was prepared by mixing 100 g of the prepolymer formulationcontaining the isocyanate-terminated polythioether with 12.20 g of thecuring composition by hand followed by mixing at 1500 rpm for 4 minusing a vacuum Hauschild mixer until the vacuum was greater than 27 inHg. The sealant was cured for 14 days at room temperature. Properties ofthe cured sealant tested according to SAE Aerospace materialsSpecification AMS-3279 Rev. C are summarized in Table 9:

TABLE 9 PROPERTY RESULTS Tack-Free Time, hours, maximum 1.5 StandardCure Time to reach 30 Durometer A, 3 hours, maximum Specific Gravity1.16 14-Day hardness, Durometer A, min. 76 Chalking None Volume Swell, %29.02 Tensile Strength, psi and elongation (%), 372/240 Standard CureTensile Strength, psi and elongation (%), After 331/390 14 days @140° F.(60° C.) in AMS2629, Type I Tensile Strength, psi and elongation (%),After 237/151 8 hours @ 350° F. (177° C.) in air Tensile Strength, psiand elongation (%), After 619/395 3 days @ 140° F. (60° C.) in AMS 2629,Type I, followed by 3 days at 120° F. (49° C.) in Air + 7 days @ 250° F.(121° C.) in air Tensile Strength, psi and elongation (%), 155/106Standard Heat Cycle as in by 7 days at 40° F. (60° C.) in AMS2629, TypeI Peel Strength, lb/inch, (% cohesive Failure) Dry (without fuelexposure) SAA per AMS2471 44 (100) Titanium C AMS4911 43 (100) MilC27725 46 (100) Mil PRF-23377, cured 150° F. 46 (100) MMS-336 Epoxyprimer (Cured 1 hour @ 45 (100) 150° F.) 7 days/JRF 1/140° F. ExposureSAA per AMS2471 41 (100) Titanium AMS4911 46 (100) Mil C27725 40 (100)Mil PRF-23377, cured 150° F. 42 (100) MMS-336 Epoxy primer (Cured 1 hour@ 53 (100) 150° F.) Mil PRF-85285 over Mil-PRF-23377 43 (100)

Finally, it should be noted that there are alternative ways ofimplementing the embodiments disclosed herein. Accordingly, the presentembodiments are to be considered as illustrative and not restrictive.Furthermore, the claims are not to be limited to the details givenherein, and are entitled their full scope and equivalents thereof.

What is claimed is:
 1. A composition comprising an isocyanate-terminatedpolythioether prepolymer, wherein the isocyanate-terminatedpolythioether comprises reaction products of reactants comprising: apolythioether polyol, wherein the polythioether comprises reactionproducts of reactants comprising a thiol-terminated polythioether and ahydroxy-functional vinyl ether; and a diisocyanate.
 2. The compositionof claim 1, wherein the molar ratio of thiol-terminated polythioether tohydroxy-functional vinyl ether is about 1:2.
 3. The composition of claim1, wherein the polythioether polyol comprises a polythioether polyolselected from a polythioether diol, a polythioether triol, and acombination thereof.
 4. The composition of claim 1, wherein thethiol-terminated polythioether comprises the reaction products of one ormore compounds of Formula (15); one or more compounds of Formula (16);and one or more polyfunctionalizing agents:HS—R¹—SH  (15)CH₂═CH—O—[—R²—O-]_(m)—CH═CH₂  (16) wherein: each R¹ is independentlyselected from C₂₋₆ alkanediyl, C₆₋₈ cycloalkanediyl, C₆₋₁₀alkanecycloalkanediyl, —[(—CH₂—)_(p)—X-]_(q)—(—CH₂—)_(r)—, and—[(—CH₂—)_(p)—X-]_(q)—(—CH₂—)_(r)—, wherein at least one —CH₂— group issubstituted with a methyl group; each R² is independently selected fromC₂₋₆ alkanediyl, C₆₋₈ cycloalkanediyl, C₆₋₁₀ alkanecycloalkanediyl,—[(—CH₂—)_(p)—X-]_(q)—(—CH₂—)_(r)—, —[(—CH₂—)_(p)—X-]_(q)—(—CH₂—)_(r)—;each X is selected from —O—, —S— and —NR¹⁰—, wherein R¹⁰ is selectedfrom hydrogen and methyl; each m is independently selected from arational number from 0 to 10; each p is independently selected from aninteger from 2 to 6; each q is independently selected from an integerfrom 0 to 5; and each r is independently selected from an integer from 2to
 10. 5. The composition of claim 1, wherein the polythioether polyolcomprises a polythioether polyol selected from a polythioether polyol ofFormula (20), a polythioether polyol of Formula (21), and a combinationthereof;R¹³—S—R¹—[—S—(CH₂)₂—O—[—R—O-]_(m)—(CH₂)₂—S—R¹-]_(n)—S—R¹³  (20){R¹³—S—R¹—[—S—(CH₂)₂—O—[—R²—O-]_(m)—(CH₂)₂—S—R¹—]_(n)—O—}_(z)—B  (21)wherein: each R¹ is independently selected from C₂₋₆ alkanediyl, C₆₋₈cycloalkanediyl, C₆₋₁₀ alkanecycloalkanediyl,—[(—CH₂—)_(p)—X-]_(q)—(—CH₂—)_(r)—, and—[(—CH₂—)_(p)—X-]_(q)—(—CH₂—)_(r)—, wherein at least one —CH₂— group issubstituted with a methyl group; each R² is independently selected fromC₂₋₆ alkanediyl, C₆₋₈ cycloalkanediyl, C₆₋₁₀ alkanecycloalkanediyl, and—[(—CH₂—)_(p)—X-]_(q)—(—CH₂—)_(r)—; each X is selected from —O—, —S— and—NR¹⁰—, wherein R¹⁰ is selected from hydrogen and methyl; B representsthe core of an z-valent polyfunctionalizing agent B(R⁸)_(z), whereineach R⁸ is selected from a group that is reactive with a —SH group and a—CH═CH₂ group; each m is independently selected from a rational numberfrom 0 to 10; each n is independently selected from an integer from 1 to60; each p is independently selected from an integer from 2 to 6; each qis independently selected from an integer from 0 to 5; each r isindependently selected from an integer from 2 to 10; and z is selectedfrom an integer from 3 to 6; and each R¹³ is independently —(CH₂)₂—O—R⁵where each R⁵ is independently —(CH₂)_(t)—OH where each t isindependently selected from an integer from 1 to
 6. 6. The compositionof claim 5, wherein each R¹³ is —(CH₂)₂—O—(CH₂)₄—OH.
 7. The compositionof claim 1, wherein the hydroxy-functional vinyl ether comprises4-hydroxybutyl vinyl ether.
 8. The composition of claim 1, wherein thediisocyanate comprises an aliphatic diisocyanate.
 9. The composition ofclaim 1, wherein the diisocyanate comprises 4,4′-methylene dicyclohexyldiisocyanate.
 10. The composition of claim 1, wherein a molar ratio ofthe diisocyanate to the polythioether polyol is at least 2 to
 1. 11. Thecomposition of claim 1, comprising a curing agent.
 12. The compositionof claim 11, wherein the curing agent comprises an aromatic amine. 13.The composition of claim 11, wherein the aromatic amine is selected fromdiethyltoluenediamine, dimethylthiotoluenediamine, and a combinationthereof.
 14. The composition of claim 1, comprising a polyfunctionalsilane.
 15. The composition of claim 14, wherein the polyfunctionalsilane is selected from bis(triethoxysilylpropyl)amine,bis(triethoxysilylpropyl)tetrasulfide, and a combination thereof. 16.The composition of claim 1, comprising an isocyanate-terminatedpolyformal.
 17. The composition of claim 1, formulated as a sealant. 18.A composition comprising: an isocyanate-terminated polythioetherprepolymer, wherein the isocyanate-terminated polythioether comprisesreaction products of reactants comprising: a polythioether polyol,wherein the polythioether polyol comprises reaction products ofreactants comprising a thiol-terminated polythioether and ahydroxy-functional vinyl ether; and a diisocyanate; an curing agentcomprising an aromatic amine; and a polyfunctional silane.
 19. Thecomposition of claim 18, wherein, the polythioether polyol comprises apolythioether polyol selected from a polythioether polyol of Formula(20), a polythioether polyol of Formula (21), and a combination thereof;R¹³—S—R¹—[—S—(CH₂)₂—O—[—R²—O-]_(m)—(CH₂)₂—S—R¹-]_(n)—S—R¹³  (20){R¹³—S—R¹—[—S—(CH₂)₂—O—[—R²—O-]_(m)—(CH₂)₂—S—R¹—]_(n)—O-}_(z)—B  (21)wherein: each R¹ is independently selected from C₂₋₆ alkanediyl, C₆₋₈cycloalkanediyl, C₆₋₁₀ alkanecycloalkanediyl,—[(—CH₂—)_(p)—X-]_(q)—(—CH₂—)_(r)—, and—[(—CH₂—)_(p)—X-]_(q)—(—CH₂—)_(r)—, wherein at least one —CH₂— group issubstituted with a methyl group; each R² is independently selected fromC₂₋₆ alkanediyl, C₆₋₈ cycloalkanediyl, C₆₋₁₀ alkanecycloalkanediyl, and—[(—CH₂—)_(p)—X-]_(q)—(—CH₂—)_(r)—; each X is selected from —O—, —S— and—NR¹⁰—, wherein R¹⁰ is selected from hydrogen and methyl; B representsthe core of an z-valent polyfunctionalizing agent B(R⁸)_(z), whereineach R⁸ is selected from a group that is reactive with a —SH group and a—CH═CH₂ group; each m is independently selected from a rational numberfrom 0 to 10; each n is independently selected from an integer from 1 to60; each p is independently selected from an integer from 2 to 6; each qis independently selected from an integer from 0 to 5; each r isindependently selected from an integer from 2 to 10; and z is selectedfrom an integer from 3 to 6; and each R¹³ is independently—(CH₂)₂—O—(CH₂)₄—OH; the curing agent comprises an aromatic amineselected from diethyltoluenediamine, dimethylthiotoluenediamine, and acombination thereof; and the polyfunctional silane is selected frombis(triethoxysilylpropyl)amine, bis(triethoxysilylpropyl)tetrasulfide,and a combination thereof.
 20. A method of sealing a surface,comprising: mixing the composition of claim 17 with a curing agent toprovide an uncured sealant; applying the uncured sealant to a surface;and curing the sealant to seal the surface.